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I 








f ^ 



CATALYSIS ,..^-;;f ;;■ 

IN 

OEGANIC CHEMISTRY 



PAUL ^ABATIER 



TranOaMbj/ 

E. EMMET REID 

PBonaaoR or oiuujao c mMi Hrjti 

JOHNB BOPKim OinVBBfllTT 



NEW YORK 

D. VAN NOSTRAND COMPANY 

Eioar Wajuon Stbot 

1922 



• • • 



• ■ 



• • • 



• • • •' 






• « 



• * 



• « • « 

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• • 






* 



CX>FyBIQHT; 1032 
BY D. VAN N08TRAND COMPANY 



Printed in the United States of America 



PREFACE 

By his remarkable investigationB on catalysis. Professor Sabatier 
has opened up new fields rich in scientific interest and fruitful in 
technical results. Catalytic hydrogenation will ever be an important 
chapter in chemistry. He is a teacher as well as an investigator and 
has done an important service in collecting from scattered sources a 
vast amount of information about catalysis and bringing tiie facts 
together in convenient and suggestive form in his book. I deem it 
a privilege to render his masterly work more accessible to English* 
speaking chemists. 

The text and the unsigned footnotes represent Professor Sabatier's 
work as closely as I can make them. I have retained the charac- 
teristic italics. I have added a few notes which are signed by those 
responsible for them. In this connection I wish to thank my friends, 
among them Dr. Gibbs, Dr. Ittner, Dr. Adkins, and Dr. Richardson, 
for assistance, Professor Gomberg for verifying a niunber of Russian 
references, and Professor H. H. Lloyd for aid in proofreading. 

To the chapter on the theory of catalysis, I have added an illumi- 
nating extension by Professor Bancroft, Chairman of the Committee 
on Catalysis of the National Research Council. In order to make 
the vast amount of detailed information in the book more readily 
available, I have prepared a subject index of some seven thousand 
entries and an author index of about eleven himdred names. 

It is a pleasure to present a brief sketch of his life and abounding 
activities. 

I have taken great pains to check the hundreds of references, but 
doubtless errors will be foimd. Corrections of any kind will be 
appreciated if sent me. 

E. Emmet Reid. 

Johns Hopkins UNiynenr^ 

BAUnMOBB, Md. 

August* 1021. 



500141 



TABLE OF CONTENTS 

[Referanoes are to Paragraphs] 

CHAPTER I 

CATALYSIS IN OBNSRAL 

DmNinoN Qv Gataltbib 1 

HuTomcAL 4 

DivniBiTT m Cataltbib 5 

Homogeneous qrstems 6 

Heterogeneous qrstems 7 

AtraOGATALTBIB 8 

Nbqativb Cataltb» 9 

Stabilisers 18 

Revenal of Catalytie Reaetiona 14 

Reversible reactions, Limits 19 

Velocity o] CatalyUc Reactumt 28 

Influence of Temperature 24 

Influence of Pressure 80 

Influence of Mass of Catalyst 82 

CHAPTER U 

ON CATALYSTS 

SolvenU 88 

Divbbsb Matbbialb can gausb Cataltbib 41 

BlemenU as CatalyBta 42 

Non-metals 48 

Metals 80 

Nickel, Conditions of Preparation 88 

Copper 60 

Platinum, Various Forms used 61 

Colloidal Metals, Methods of Preparation 87 

(kndeM aa CatalyaU 73 

Water 78 

MetaUic Oxides 76 

Influence of their Phsraical State 76 

Mineral Acidi 81 

Biuea 83 

Fluoridea, Chloride; Bromidee, lodidee 84 

Cyanides 06 

Inorganic 8alU of Oxygen Acids 06 

Variotu Compovndt 104 

Dubation or trb Action of Cataltbts Ill 

Poisoning of Nickel 112 

Poisoning of Platinum 116 

Fouling of Catalysts 118 

Regeneration of Cataljrsts 128 

MiaUun of CatalyBU vfUh Inert MateridU 128 

▼tt 



viii CONTENTS 

CHAPTER m 
MECHANISM OP CATALYSIS 

Ideas of Benelius 120 

Physical Theory of Catalysis 131 

Properties of Wood Charcoal 131 

Heat of Imbibition 133 

Absorption of Gas by finely divided Metals 136 

Physical Interpretation of their Catal3rtic R61e 138 

Insufficiency of the Physical Theory 141 

Chemical Theory of Catalysis 145 

Reciprocal Catalysis 146 

Induced Catalysis 149 

Auto-oxidations 150 

Oxidation Catalysts 152 

Catalysis with Isolatable Intermediate Compounds 156 

Action of Iodine in Chlorination 156 

Catalysis in the Lead Chamber 158 

Action of Sulphuric Acid on Alcohols 159 

Method of Squibb 161 

Use of Copper in Oxidations 162 

Action of Nickel on Carbon Monoxide 163 

Catalysis toithout Isolatable Intermediate Compounds 164 

Hydrogenation with Finely Divided Metals 165 

Dehydration with Anhydrous Oxides 169 

Decompositions of Acids 171 

The Friedel and Crafts Reaction 173 

The Action of Acids and Bases in Hydrolysis 175 

Advantages of the Theory of Temporary Cornbinations 180 

Theories of Catalysis by W. D. Bangboft 180a 



CHAPTER IV 

ISOMERIZATION — POLYMERIZATION — 
DBPOLYMBRIZATION — CONDENSATIONS BY ADDITION 

8 1. Isomerization 181 

Changes of Geometrical Isomers 182 

Changes of Optical Isomers 186 

Migration of Double and Triple Bonds 190 

Decydizations 193 

Cyclizations and Transformations of Rings 194 

Migration of Atoms 199 

fi 2. Polymerizations 209 

Ethylene Hydrocarbons 210 

Acetylene Hydrocarbons 212 

Cydio Hydrocarbons 216 

Aldehydes 218 

Aldolisation 219 

Polyaldehydes 222 

Passage into Esters ' 225 

Ketones 229 

Nitrites and Amides 230 

13. Depolymerixations • 234 

fi 4. Condensation by the Addition of Dissimilar Molecules 236 



CONTENTS b 

Aldehydes and Nitro-Compounds 236 

Ketones 238 

Acetylation of Aldehydes 240 

Hydrocarbons 241 



CHAPTER V 
OXIDATIONS 

L Direct Ozidation with Gaseous Oxygen 244 

daaaification of Direct Oxidations 244 

Platinum and Related Metals 245 

Copper 253 

Various Metals 254 

Carbon 257 

Metallic Oxides 258 

Metallic Chlorides 263 

Manganese Salts 264 

Oxidation of Oils 265 

Silicates 267 

n. Oxidation effected by Oxygen Compounds 268 

^ydrogen Peroxide 268 

Nitric Add 269 

Hypochlorites 270 

Chlorates 271 

Sulphur Trioxide 272 

Permanganates 275 

Persulphates .* 276 

Nitrobenzene 277 



CHAPTER VI 

VARIOUS SUBSTITUTIONS IN MOLECULES 

S 1. Introduction of Halogens 278 

ChlorinaUon 278 

Iodine 278 

Bromine 270 

Sulphur 280 

Phosphorus 281 

Carbon 282 

Metallic Chlorides 283 

Aluminum Bromide 289 

BrommaUotk 200 

Iodine 291 

Manganese 292 

Metallic Chlorides or Bromides 293 

lodmaUon 294 

1 2. Introduction of Sulphur 295 

8 3. Introduction of Sulphur Dioxide 297 

S4. Introduction of Carbon Monoxide 298 

S 5. Introduction of Metallic Atoms 299 

Formation of Alcoholates 299 

Formation of Organo-magnesiimi Complexes 300 



X CONTENTS 

CHAPTER Vn 

Hydration 

GlaaBification of Hydratioiu 905 

Addition of Water 306 

Ethylene Compounds 306 

Acetylene Derivatives 308 

Nitriles and Imides 311 

Addition of Water with Decomposition, in Liquid Medium 818 

Hydrolysis of Esters 313 

Use of Acids 313 

Use of Bases 318 

Hydrol3r8is of Chlorine Derivatives 320 

Ethers 821 

Acetals 322 

Polysaccharides 323 

Olucosides 327 

Amides and their Analogs 331 

Addition of Water with Decomposition, in Gaseous Medium 337 

Hydrolsrsis of Esters 337 

Ethers 338 

Carbon Disulphide 339 

Alcoholysis 340 

CHAPTER Vra 
HYDROGBNATION 

Hydrogenation in Gaseous System, Generalities, Use of Nickel 343 

Historical 343 

Method of Sabatier and Senderens 343 

Hydrogen Generator 346 

Reaction Tube 347 

Introduction of the Substance 350 

Receiver for Collecting the Products 355 

Hydrogenation over Nickel 358 

Duration of the Activity of the Metal 359 

Choice of Reaction Temperature 361 

RBSui;r8 or Htdrocbnation ovib Nickxl in Gaseous Ststbm 366 

Reduction trithout addition of hydrogen 367 

Nitrous Oxide 388 

Aromatic Alcohols 360 

Phenols and Poljrphenols above 250* 370 

Furfuryl Alcohol 371 

Carbon Disulphide at 500* 372 

Reductions with Simidtaneous Addition of Hydrogen 373 

Oxides of Nitrogen 874 

Aliphatic Nitro Derivatives 377 

Aromatic Nitro Derivatives 378 

Nitrous Esters 382 

Oximes 383 

Aliphatic Amides 386 

Ethyl Aoeto-aoetate 387 

Aromatic Aldehydes 388 

Aromatic Ketones 389 

Aromatic Diketones 391 



CONTENTS xi 

Anhydrides of Dibaaio Adds 893 

Carbon Monoxide 993 

Carbon Dioxide 395 

Application to the Manufacture of Illuminating Gas 397 

Aromatic Halogen Derivatives 403 

Halogenated Aliphatic Adds 407 



CHAPTER IX 

HYDROGENATION (Continued) 

Hydrogenation in Gaseoua System* Use of Nickel (Continued) 406 

Addition of Hydrogen 408 

1. Direei Addition of Hydrogen to Carbon 409 

2. Addition to Hydrogen at Ethylene Double Bond 412 

Hydrocarbons 413 

Unsaturated Alcohols 416 

Esters 417 

Ethers 418 

Unsaturated Aldehydes 419 

Unsaturated Ketones 420 

Unsaturated Acids 422 

3. Acetylene Triple Bond 423 

4. Triple Bond between Carbon and Nitrogen 426 

Aliphatic Nitriles -. 427 

Aromatic Nitriles 428 

Di<^3ranide8 429 

5. Qtuuintple Bond between Carbon and Nitrogen 430 

Isocyanides T 431 

6. Double Bond between Carbon and Oxygen 432 

Aliphatic Aldehydes 432 

Aromatic Aldehydes 433 

Pyromucic Aldehyde 434 

Aliphatic Ketones 435 

Qyclo-«liphatic Ketones 436 

Ketone-adds 437 

Diketones 438 

Aromatic Ketones 441 

Quinones 442 

Ethylenic Oxides 443 

7. The Aromatic Nucleus 444 

Aromatic Hydrocarbons 446 

Polycydic Hydrocarbons 452 

Aromatic Ketones 455 

Phenols 456 

Polsrphenols 460 

Phenolic Ethers 464 

Aromatic Alcohols 465 

Aromatic Amines 466 

Aromatic Adds 471 

S.Variou8 Ringe 472 

Trimethylene Ring 472 

Tetramethylene Ring 473 

PentameUiylene Ring 474 

Hexamethylene Ring 475 

Terpenes 477 



ni CONTENTS 

Heptameihylene Ring 479 

Octomethylene Ring 480 

Naphthalene Nucleus 481 

.Anthracene Nucleus 483 

Phenanthrene Nucleus 484 

Pyrrol 488 

Pyridine 486 

Quinoline 488 

Carbasol 490 

Acridine 491 

9. Carbon Dmdpkide 492 

Htdbogbnation with DsooMFOBinoN 493 

Hydrocarbons 493 

Alcoholic or Phenolic Ethers 494 

Phenyl Isopyanate 495 

Amines 496 

Diaso Compounds 497 

Indol 497 



CHAPTER X 
HYDROGENATION (Continued) 

S 1. Hydrogenation in Gaseous System over Various Metals 498 

Cobalt 499 

Ethylenic Hydrocarbons 600 

Acetylene 601 

Benzene and its Homologs 602 

Aldehydes and Ketones 603 

Oxides of Carbon 604 

Iron r 606 

Ethylenic Hydrocarbons 606 

Acetylene 606 

Copper 607 

Reduction of Carbon J)ioxide 608 

Nitro Derivatives 609 

Nitrous Esters 613 

Ozimes 614 

Ethylenic Compounds 616 

Acetylene Compounds 618 

Nitriles 621 

Aldehydes and Ketones 622 

Platinum 624 

Combination of Carbon and Hydrogen 626 

Ethylene Compounds 620 

Acetylene Compounds 627 

Hydrocsranic Add 628 

Nitro Derivatives 629 

Aliphatic Aldehydes and Ketones 632 

Aromatic Nucleus 634 

Pobrmethylene Rings 636 

Pattadium 636 

S 2. Hydrogenation by Nascent Hydrogen in Gaseous System 637 

Use of Alcohol Vapors 638 

Use of Formic Acid Vapors 639 

Use of Carbon Monoxide and Water Vapor 640 



CONTENTS xiii 

GHAPTEB XI 
HYDROGENATION (Continued) 



Direct Hydrogenation of Liquids in Contact with Metal Catalysts . . 541 

Hifltorical 542 

General Conditions of the Reaction 543 

51. Method of Paal 544 

Vie of Colloidal PaUadium 545 

Reduction with Fixation gI Hydioc^ 545 

Addition of Hydrogen 546 

Application to Alkaloids 565 

Use of Colloidal PUUmum 556 

52. Method of Willstitter 562 

Method of Operating 562 

Use of Platinum Black 562 

Nitro Derivatives : 564 

Ethylene Double Bonds 565 

Acetylene Triple Bonds 566 

Alddiydee and Ketones 567 

The Aronuttic Nucleus 569 

Terpenes 570 

Complex Rings 571 

Use of PaUadikun Black 573 

Reduction of Carbonates to Formates 574 

Reduction of Acid Chlorides 575 

Nitro Derivatives 576 

Double and Triple Carbon Bonds 577 

Qydic Compounds 578 

Vee of other Metals of Platinum Group 580 



CHAPTER Xn 
HYDROGENATION (Continued) 

Direct Hydrogenation of Liquids in Contact with Metal 

Catalysts (Cont.) 584 

{3. Method of Ipatief 584 

Apparatus Used 585 

Use of Nickel 585 

Formation of Methane 586 

Ethylene Double Bonds 587 

Aldehydes and Ketones 588 

Aromatic Nucleus 580 

Terpenes 501 

Various Ringi 502 

Use of Iron 603 

Use of Copper 504 

Use of Other MetfOs 505 

i 4. Hydrogenation of Liquids in Contact with Nickel under Low 

Pressnret 596 

Apparatus of Brochet 507 

Alleged Activity of Oxides 508 

Method of Operating 500 

ResuUs Obtained 600 

MtK) Derivativea WO 



xiv CONTENTS 

Ethylene Compounds (M)l 

Aldehydes and Ketones 602 

Various Rings 008 

Use of Nascent Hydrogen in Liquid System in Contact with 

Metals 604 



CHAPTER Xm 
VARIOUS ELIMINATIONS 

{1. Elimination of Halogens 606 

S 2. Elimination of Nitrogen 606 

Diaso Compounds 606 

Hydrasine Derivatives 611 

S 3. Elimination of Free Carbon 613 

Decarbonixation of Carbon Mcmoxide 614 

i 4. Elimination of Carbon Monoxide 618 

Action of Nickel 610 

Action of Other Metals 621 

S 5. Elimination of Hydrogen Sulphide 626 

Mercaptans 626 

Thiophenols 620 

Formation of Thioureas 630 

{ 6. Elimination of Ammonia 631 

Action of Nickel on Aliphatic Amines 631 

Phenylation of Aromatic Amines 632 

Decomposition of Phenylhydrasones 633 

i 7. Elimination of Aniline 634 



CHAPTER XIV j 

DEHYDROQENATION 

Historical 636 

Classification of Dehydrogenations 638 

S 1. Dehydrogenation of Hydrocarbons 630 

S 2. Dehydrogenation of Hydrocydic Compovids 640 

Qyclohexane Compounds 641 

Hydrides of Naphthalene, Anthracene, etc 642 

Terpenes 643 

Piperidine 647 

Action of Palladium 649 

S 3. Dehydrogenation of Alcohols 660 

Mechanism of the Decomposition of Alcohols 660 

Use of Copper 663 

Primary Alcohols, Preparation of Aldehydes 663 

Secondary Alcohols, Preparation of Ketones 669 

Uee of Nickel 664 

Uae of CobdU 666 

Use of Iron 667 

Use of PlaUnum 668 

Use of PaUadium 669 | 

Use of Zinc «70 

Use of other Substances 071 



CONTENTS rv 

Manganous Oxide G72 

Stannous Oxide C73 

Cadmium Oxide 674 

Other Oxides: their Classification 675 

Case of Methyl Alcohol 676 

Carbon 679 

i A. Dehydrogenation of Polyalcohols 680 

{ 5. Dehydrogenation of Amines 681 

Primaiy Amines, Return to Nitrile 681 

Secondary and Tertiary Aminee 682 

i 6. Synthesis of Amines 683 

1 7. Ring Formation by Blimination of Hydrogen 684 

Use of Nickel 684 

Use of Aluminum Chloride 685 

Use of Anhydrous Oxides 686 

CHAPTER XV 

DEHYDRATION 

Dehydration Catalysts 687 

i 1. Dehydration of Alcohols Alone 688 

FoBMATioN OP Ethbbs 600 

In Liquid Mediimi 601 

In Gaseous System 603 

DaHTDRATioN TO Htdbogabbons 605 

Reaction in Liquid Medium 605 

Concentrated Mineral Acids 606 

Zinc Chloride 608 

Iodine 600 

Eeaction in Gaseoua System 700 

Elements 700 

Anhydrous Metallic Oxides 702 

Conditions which Regulate their Action 706 

Alumina 713 

Blue Oxide of Tungsten 715 

Thoria 716 

Metallic Salts 717 

Case of Benzhydrol 720 

Catalytic Passage of an Alcohol to a Hydrocarbon 721 

Dehydration with Simultaneous Hydrogenation 722 

DiHTDRATION OF PoLTALOOHOLS 723 

Reaction in Gaseous System 726 

Ring Formation by the Dehydration o/ Polyalcohols 727 



CHAPTER XVI 

DEHYDRATION (Continued) «; 

i 2. Dehydration of Alcohols with Hydrocarbons 728 

S 3. Dehydration of Alcohols with Ammonia pr Amines 720 

Reaction in Liquid System 720 

Reaction in Gaseous System 731 

Mixed Amines 738 

Alkyl-piperidinee 741 

Pjnrol •• • 7u 



xvi CONTENTS 

{4- Dehydration of Alcohols with Hydrogen Sulphide: Synthesis of 

Mercaptsns 743 

Comparison of the Activity of Various Oxides 743 

S 5. Dehydration of Alcohols with Acids: Esterification 747 

Catalytic Esterification in Liquid Medium 748 

Use of Mineral Acids 749 

Explanation of their Action 752 

The Case of Glycerine 760 

Use of Aoetanhydride 761 

Catalytic Esterification m Gaseous System 762 

Mechanism of the Action of Oxides 763 

Case of Bensoic Esters 766 

Use of Titania 767 

Laws of Esterification over Titania 770 

Case of Formic Esters 773 

Esterification Rates 775 

Use of Berylia 778 

S 6. Dehydration of Alcohols with Aldehydes or Ketones 770 

Formation of Acetals 780 

Formation of Hydrocarbons 784 



CHAPTER XVn 

DEHYDRATION (Continued) 

S 7. Dehydration of Phenols Alone 785 

Preparation of Simple Phenol Ethers 787 

Diphenylene Oxides 787 

Mixed Phenol Ethers 788 

{8. Dehjrdration of Phenols with Alcohols: Synthesis of Alkyl 

Phenol Ethers 780 

1 0. Dehydration of Phenols with Amines 700 

{10. Dehydration of Phenols with Hydrogen Sulphide: Formation 

of Thiophenols 701 

S 11. Dehydration of Phenols with Aldehydes 702 

{ 12. Formation of Phenolic Glucosides 703 

9 13. Dehydration of Aldehydes or Ketones 704 

Crotonisation of Aldehydes Alone 705 

Crotonixation of Ketones Alone 707 

Crotonization of Aldehydes with Ketones 708 

CroUmigation in Gaseous System 801 

Dehydration of a Single Molecule 802 

CoruUnsation of Aldehydes or Ketones with Various Organic Mole- 
cules 803 

S 14. Dehydration of Aldehydes or Ketones with Ammonia 807 

S 15. Dehydration of Aldehydes with Hydrogen Sulphide 810 

S 16. Dehydration of Amides 811 

Formation of Nitriles 811 

Transformation of Acid Chlorides into Nitriles 812 

S 17. Dehydration of Oximes 814 

9 18. Direct Sulphonation of Aromatic Compounds 815 

S 10. Condensations hy the Elimination of Alcohol 817 



CONTENTS xvii 

CHAPTER XVm 

DECOMPOSITION OF ACIDS 

Decomposition of Fonnic Acid 820 

Dehydrogenation Catalysts 824 

Dehydration Catalysts 825 

Mixed Catalyste 826 

Decomposition of Monobasic Organic Acids 820 

Simple EHmmation of Carbon Dioxide 831 

Aliphatic Acids 831 

Aromatic Acids 834 

SimuUaneoua EUminaiion of Water and Carbon Dioxide 837 

Preparation of Symmetrioil Ketones 837 

Use of Calcium Carbonate 839 

Use of Alumina 840 

Use of Zinc Oxide 841 

Use of Cadmium Oxide 842 

Use of the Oxides of Iron 843 

Use of Thoria 

Use of Manganous Oxide 845 

Use of Lithiimi Carbonate 840 

Formation of Ketones in Liquid Medium 847 

Preparation of Mixed Ketones 848 

Preparation of Aldehydes 851 

Decomposition of Dibasic Acids 855 

Decomposition of Acid Anhydrides 857 



CHAPTER XTX 

DECOMPOSITION OF THE ESTERS OF ORGANIC ACIDS 

{ 1. Esters of Monobasic Acids 858 

Qeneral Mechanism of this Catalysis 860 

Case of Alumina 860 

Case of Thoria 861 

Case of Titania 863 

Case of Bensoic Esters 864 

Formic Esters 866 

S 2. Decomposition of Esters with Ammonia 871 

S 3. Esters of Dibasic Acids 872 

CHAPTER XX 

ELIMINATION OF HALOGEN ACIDS OR SIMILAR 

MOLECULES 

{ 1. Separation of the Acid from a Single Molecule 876 

Use of Anhydrous Metallic Chlorides- 876 

Mechanism of this Catalysis 878 

Use of Oxides or Metals 881 

S 2. Molecular Condensations by the Elimination of a Halogen Acid 883 

Alkylation of Aromatic Molecules 884 

Method of Operating 884 

Reversal of the Reaction 887 

Results Obtained 880 



xvffi CONTENTS 

Synthem of Keione$ 891 

Method of Operatiog 893 

Results Obtftined 893 

Formation of Amides 895 

Ring Formation 896 

Mechanum of the Reaction 898 

Chlorides that may be Substituted for Aluminum Chloride 899 

Formation of Aromatic Amine* by Hofmann's Reaction 901 

Condeneatione in the Aliphatic Serie$ 902 

i 3. Separation of Alkaline Chloride, Bromide or Iodide 904 



CHAPTER XXI 

DECOMPOSITION AND CONDENSATION OF 

HYDROCARBONS 

Action of Heat on Hydrocarbone 905 

Cracking 906 

Case of Bensene 907 

Case of Petpoleimi 908 

Case of Solvent Naphtha 909 

Action of Catalysts 910 

Parafl^e Hydrocarbons 911 

Ethylene Hydrocarbons 912 

Acetylene Hydrocarbons, Acetylene 913 

First Kind of Reaction 914 

Second Kind of Reaction 916 

Superposition of the Two Kinds 917 

Cyclic Hydrocarbons 921 

Terpenes 922 

Reactions carried out in the Presence of Hydrogen 924 

Case of Acetylene 925 

Synthesis of Petroleums 926 

Theory of the Origin of Petroleum 928 

Action of Anhydrous Aluminum Chloride 929 

Applications to the Treatment of Petroleum 932 

Use of Finely Divided Metals 932 

Use of Oxides 934 

Use of Anhydrous Chlorides 935 



APPENDIX TO CHAPTERS XI AND XH 
HYDROGBNATION OF LIQUID FATS 

Nature of Liquid Fats 937 

Iodine Number 938 

History of Hydrogenation 939 

Catalysts 941 

Nickel 941 

Use of the Oxides and Salts of Nickel 943 

Palladium 946 

Life of Catalyste 947 

Neutralisation of Oils 948 

Troubles with Moisture 949 

Amotmt of Catalysts 951 



(X)NTENTS 

Temperature 962 

Hydrogen d63 

ProoesB of Bergius 964 

Volume of Hydrogen Required 966 

Appantiu 957 

Apparatus of Erdmami 968 

Apparatus of Schwoerer 969 

Apparatus of Sehlindc 960 

Apparatus of Wilbusehewitoh 961 

Apparatus of Ellis 962 

Apparatus of Kayser 963 

Apparatus of Woltman 964 

Rendu 966 

Physical Constants of Hardened Oils 966 



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Nachr. Ges. der Wtss. Gdttingen Nachrichten der koniglichen Gesellschafft der 

Wissenschaften, Gottingen. 
Phil. Mag. PhUosophiccd Magazine, London. 
Proc. Roy. Soc. Proceedings of the Royal Society, London. 
Pogg. Ann. Annalen der Physik und Chemie (Poggendorf), Leipsig. 
Quart. J. Science American Journal of Science, New Haven. 
Reo. Trav. Chim. Pays-Bas Recueil des travaux chimiques des Pays-Bas, 

Leyden. 
Rev. Mois. Revue du Mois, Paris. 
Rev. gen de chim. pure et app. Revue ginirale de chimie pure et appUquie, 

Paris. 
Rev. Set. Revue Scientifique, Paris. 
Sits. Akad. Wien. Sitsungiiyerichte der mathemaiisch^naturwissenschaftUchen 

Klasse der kaiserUchen Akademie der Wissenschaften, Vienna. 



xxii PERIODICAL^ CTTED AND THEIR ABBREVIATIONS 

Self. Zeit. Seifensieder ZeUung, 

800. Tech. Gai. SocUtd technigue de Vlnduitne gaxikre, Paris. 

800. Esp. Quim. Analen de Ic aodetad etpa^la de fisica y quimica, Madrid. 

Trans. Far. 800. Traneactume of the Faraday Society, London. 

Zeit. anorg. Chem. Zeitachrijt fur anorganieche Chemie, Hamburg. 

Zeit. f. Chem. Kritiecke ZeiUchrift fur Chemie, Phyeik und MathemaUk 

(Kekuli), Heidelberg and Gottingen. 
Zeit. Elektroch. Zeitechrift fur Elektrochemie, Halle. 
Z. phyi. Chem. ZeiUchrift fur phyeikalische Chemie, Leipsig. 



INTRODUCTION 

PAUL SABATIER 

Pattl Sabatieb was bom at Carcassonne Nov. 5, 1854. Admitted 
at the same time to the Polytechnic and the Normal School in 1874, 
he chose the latter from which he went out in 1877 receiving the 
highest grade in the competitive examination for agregation de phy^ 
rique} After spending a year as Professor at the Lyc£e of Nimes, 
he became, in October, 1878, assistant to Berthelot at the College de 
France. In July, 1880, he received the degree of Doctor of Science, 
his thesis being on Metallic Sulphides. After having been Maitre de 
Conference in physics in the Faculty of Sciences at Bordeaux for more 
than a year, he took charge, in January, 1882, of the course in physics 
in the Faculty of Sciences of Toulouse which he was never to leave. 
Taking charge of the chemistry course at the end of 1883, he was 
made Professor of Chemistry November 24, 1884, a position which 
he still occupies. 

His chemical investigations are very nimierous and touch various 
branches of that science: most of them have been published in the 
Camptes Bendua de VAcademie des Sciences, the BuUetin de la So- 
eUtS Chimique, and the Annates de Chimie et de Phisique. 

His researches in physical chemistry stretch from 1879 to 1897 
and comprise numerous thermochemical measurements (sulphides 
1879-1881, chlorides 1889, chromates 1886, copper compounds 1896- 
1897, etc.), a thorough study of tiie velocity of transformation of 
metaphosphoric acid (1887-1889), studies on absorption spectra 
(1886 and 1894), on the partition of a base between two acids 
(1886-1887), etc. 

In inorganic chemistry he has published numerous articles on 
metallic sulphides (1879-1880), the sulphides of boron and silicon 
(1880-1891), hydrogen disulphide (1886), the selenides of boron and 
silicon (1891), metallic chlorides (1881, 1894-1895), the chlorides 
(1881, 1888) and the bromide of copper (1896). A profoimd study 
of the oxides of nitrogen, which led to the characterization of metallic 
nitrides, was carried out (1897-1896) with the assistance of his pupil, 

^ The agregation is a competitiye examination which is coimidered extremely 
diffieult. 



xxiv INTRODUCTION 

J. B. Senderens. He prepared the deep blue nitrosodisulphonic acid 
(1896-1897), defined the tetracupric salts (1897), and obtamed the 
basic mixed argento-cupric salts (1897-1899) which formed the start- 
ing point for a whole series of analogous compounds which Mailhe 
prepared subsequently. 

His investigations in organic chemistry (starting in 1897) are the 
most important and include the general method of catalytic hydro- 
genation in contact with finely divided metals, which was awarded 
the Nobel prise for chemistry in 1912. The experiments involved 
in this as well as in the inverse dehydrogenation, were carried out 
with the aid of his successive pupils, J. B. Senderens (1899-1905), 
Alfonso Mailhe (190&-1919), Marcel Murat (1912-1914), L^ Espil 
(1914) and Georges Gaudion (1918-1919). 

The study of metallic oxides as catalysts led Sabatier with Mailhe 
to discover a whole series of methods of transforming alcohols and 
phenols into mercaptans, amines, ethers, esters, etc., and also trans- 
forming acids (1906-1914). At the same time he carried out, either 
with Mailhe or Murat, a large number of syntheses of hydrocarbons 
and alcohols of the cyclohexane series, etc. (1904-1915). 

In agricultural chemistry, Sabatier has published about fifteen 
memoirs on various subjects as well as Lessons on AgricvUiaral 
Chemistry. 

The Academy of Sciences of Paris awarded him the Lacaze prize 
in 1897 and the Jecker prize in 1905 and elected him correspondent 
of the chemical section in 1901, then non-resident membre titvlmre in 
April, 1913. Awarded the Nobel Prize in Chemistry in 1912, Sa- 
batier received in 1915 the Davy Medal of the Royal Society of 
London of which he was elected a foreign member in 1918. He is 
also a foreign member of the Royal Institution, the Academy of 
Sciences of Amsterdam, the Academy of Sciences of Madrid, the 
Royal Society of Bohemia, etc. 

Profoundly attached to Toulouse, where he belonged to various 
local academies, Sabatier refused to leave his University to occupy 
the chair at the Sorbonne left vacant in 1907 by the death of Moissan. 
Dean of the Facility of Sciences since 1905, he has created the three 
technical Institutes of Agriculture, of Chemistry and of Electro- 
technique which are thronged by a large number of students. 



unjv. or 

CALiFORNiA 



CATALYSIS 



IN ORGANIC CHEMISTRY 



CHAPTER I 
CATALYSIS IN GENERAL 

1. By catalysis we designate the mechanism by virtue of which 
certain chemical reactions are caused, or accelerated, by substances 
which do not appear to take any part in the reactions. 

A mixture of hydrogen and oxygen is stable at ordinary tempera- 
tures, but the introduction of a piece of platinum black causes im- 
mediate explosive combination; the platinimi black is not visibly 
affected and can repeat the same effects indefinitely. 

2. Hydrogen peroxide decomposes very slowly in cold water solu- 
tion, a 30 volume solution requiring more than 240 hours at 17* for 
50% decomposition, but the addition of 0.06 g. platinum black to 
20 cc. of such a solution causes a vigorous evolution of oxygen and 
reduces the period of half decomposition to 8 seconds at 14*.^ The 
platinum black, which does not seem to be altered, has by its presence 
enormously accelerated the reaction which normally takes place 
spontaneously but very slowly. 

3. Substances which provoke or accelerate reactions without them- 
selves being altered are called catalysts. 

4. History of Catalysis. The first scientific observation of a 
catalytic transformation appears to be due to Kirchhof , ' who, in 
1811, showed thatgnineral acids, in hot water solution, change starch 
into dextrine and sugar, without being themselves altered by the 
reaction. 

A short time afterwards, in 1817, Sir Humphrey Davy • observed 
that a slightly heated platinum spiral introduced into a mixture of 
air and a combustible gas, hydrogen, carbon monoxide, or hydro- 
cyanic acid, becomes incandescent and causes the slow oxidation of 

^ Lbmoinb, Compt, rend^ z69, 057 (1916). 
> KmcHHOP, Schweigger^s Jour. 4, 108 (1812). 
* Datt, H., Pha. Trans., 97> 45 (1817). 



* • • • - • • 



:CATALYSIS IN ORGANIC CHEMISTRY • 2 

the gas/* lii*1820 Edmond Davy* discovered that platinum black 
• . }/^ v?^? *??1*? 4icphbl with which it is wetted. Platinum sponge also 
possesses this power of provoking reactions without undergoing any 
appreciable change, and in 1831, Pelegrin Phillips," a vinegar manu- 
facturer of Bristol, took out an English patent on the use of plati- 
num sponge to oxidise by air the sulphur dioxide obtained by roast- 
ing pyrites, thus producing sulphur trioxide. This was the germ of the 
contact process for the manufacture of sulphuric acid, which required 
the labors of half a century to render it industrially practicable. 

In his masterful Treatise cm Chemistry, Berzelius* discussed 
phenomena of this kind in which the presence of a material apparently 
having nothing to do with a reaction can yet cause that reaction to 
take place. Adopting a term which had been used in the seventeenth 
century by Libavius^ with a different meaning, he grouped these 
phenomena under the designation catalytic, from the Greek xdra 
dovm, and Xuw^ loose, I unloose. 

5. Diversity in Catalysis. The reactions in which catalysis is 
observed have multiplied with the advance of chemistry. They are 
extremely varied but can be divided into two distinct groups. 

6. First we have catalysis in a homogeneous system, that is, where 
there is an intimate mixing of the various constituents, or at least 
between one of them and the catalyst that causes or accelerates the 
reaction. This is the case with the soluble ferments which are not 
considered in this treatise; it is also the case with water vapor in 
gaseous mixtures; with iodine, sulphur and various metal chlorides 
employed to aid chlorinations; with mineral acids in aldolization or 
crotonization as well as in the folmation or saponification of esters; 
with alkalies in saponification; with ferrous or manganous salts in 
oxidations; with zinc chloride in the dehydration of alcohol; with 
mercwrous sulphate in the sulphonation of aromatic compoimds; with 
anhydrous ether in the preparation of organo-magnesium complexes; 
and even doubtless, in the Friedel and Crafts reaction with aluminum 
chloride which is partial|y soluble in the liquids used. 

7. The second group is that of h^trogeneous systems in which, for 
example, a solid catalyst is brought into contact with gaseous or liquid 
systems capable of reacting. It acts only by its surface, if it is com- 
pact and remains so during the reaction; by all its mass if it is 

* Davt, E., Schweigget^s Jour, 34, 91 (1822); 38, 321 (1823). 
« English patent 6,069 of 1831. 
« Behzbuus, Traits de Chemie, I, 110 (1845). 

' LiBAVius, Alchemia, Lib. n, vol. I, chapters XXXIX and XL, Frankfort, 
1611. 



3 CATALYSIS IN GENERAL 10 

porous, its surface then being extremely large as compared with its 
weight. The influence of the almost indefinite extension of the sur- 
face in the finely divided state is such that we are tempted to think 
of the catalytic activity of a material as belonging exclusively to 
that state (130). 

8. Autocatalysis. Ostwald has designated by this term those 
reactions in which the products of the reactions accelerate the re- 
actions. 

Thus hydrogen and oxygen, rigorously dried, do not combine even 
at 1000^, but if the combination is once started, the water vapor so 
formed greatly favors the reaction, rendering it excessively rapid and 
explosive. 

The decomposition of hydrogen selenide,^ of arsine* and of 
Btibine^^ are cases of autocatalysis, since the selenium, arsenic, and 
antimony set free accelerate the reactions when once they are started. 

Pure nitric acid acts only slowly on many pure metals, silver, cop- 
per, bismuth, cadmium, and mercury, but when once started, the 
reaction accelerates itself because nitrous fumes are produced which 
facilitate the attack so that the reaction may become violent.^^ 

We find further examples of autocatalysis in the spontaneous 
changes which certain organic nitro compounds undergo, e. g, powders 
with nitrocellulose as a base, such as powder B;^' these changes 
produce acid vapors which accelerate the decomposition. 

9. Negative Catalysts. Certain materials, when present in a 
chemical system, exercise an unfavorable or retarding influence ; such 
are negative catalysts, the presence of which increases rather than de- 
creases the chemical friction and may sometimes even paralyze the 
normal play of affinities. 

10. For the present, it is convenient to place in this class sub- 
stances capable of altering positive catalysts so as to diminish their 
efficient action. 

As early as 1824, Turner*' observed that traces of various sub- 
stances suppressed the catalytic activity of finely divided platinum 
and mentioned as such ammonium sulphide, carbon disulphide, and 
hydrogen sulphide. 

• B(»>iNSTBiN, Zeit. physih. Chem,, ag, 428 (1800). 

• CoHBN, Zeit. physik, Chem,, ao, 303 (1806). 

^^ Stock and Guttmann, Berichte, 37, 001 (1004). Bodbnstein, Ibid, p. 1361. 
11 Vblit, Jour. 80C. Chem. Ind., xo, 204 (1801). 

^* The French cannon powder which was used during the World War. It 
is pure nitrocellulose gelatinized by a mixture of 2 parts ether to 1 part alcohol. 
^* TxmnoL, Pogg. Ann., 2, 210 (1824). 



U CATALYSIS IN ORGANIC CHEMISTRY 4 

In the manufacture of sulphuric acid by the contact process the 
presence of vapors of mercury, phosphorus, and particularly arsenic 
in the gas is sufficient to impair rapidly and destroy ultimately the 
catalytic action of the platinized asbestos. 

In the use of finely divided nickel as a catalyst for direct hydro- 
genation, traces of chlorine, bromine, iodine, or sulphur compounds 
in the metal, in the hydrogen, or in the substance to be treated, suf- 
fice to prevent the reaction completely and somehow act as veritable 
poisons for the mineral ferment.^* 

Many other substances, without being toxic to the nickel, which 
they do not seem to injure, can retard the hydrogenation by their 
presence, e. g. glycerine, various organic acids, etc. Examples will 
be given in Chapter II (112 et seq,). In hydrogenations with nickel, 
the presence of small amoimts of carbon monoxide in the hydrogen 
exercises a marked retarding infiuence.^^ ^* 

11. Negative catalysts, which by their presence, stabilize a chem- 
ical system and render its transformation more difficult, have been 
less studied than positive, but numerous examples may be given. It 
has long been known that hydrogen peroxide keeps better when 
slightly acid. The addition of a few himdredths of one per cent of 
sulphuric or hydrochloric acid to a 30 volume hydrogen peroxide 
considerably augments its stability. Thus at 65^, pure hydrogen 
peroxide required 3.2 hours for 50 per cent decomposition but this 
was increased to 35 hours by the addition of 0.026 molecule of hydro- 
chloric acid.^^ 

The spontaneous oxidation of chloroform to carbonyl chloride is 
hindered by the presence of a little alcohol. 

Hydrocyanic acid is stabilized by traces of hydrochloric or sul- 
phuric acid." 

In the oxidation of phenols by hydrogen peroxide in the presence 
of ferric chloride as catalyst, the reaction is retarded by the presence 
of mineral acids and even more by acetic, oxalic, and citric acids.^* 

The formation of the organo-magnesium halides in the Grignard 
reaction is retarded by the presence of anisol, ethyl acetate, chloro^ 
form or carbon dmtlphide (303). 

^« Sabatibb, Berichte, 44, 1984 (1911). 

1" Maxtkd, Chem. Netn, 1x7, 73 (1918). 

10 Numerous quantitative experiments made by the translator in the Lab- 
oratoiy of Colgate and Company showed that catalytic nickel for hydrogenation 
IB more injured, in uae, by carbon monoxide than by any other catalsner poison 
that is apt to be present. — £. E. R. 

^7 laMoam, Compt. rend^ x6z, 47 (1915). 

» LnDiG, Anntden, z8» 70 (1836). 

^* CouN and Si^NicHAi^ Compt. rend, 153, 76 (1911). 



5 CATALYSIS IN GENERAL 18 

In the abstraction of halogens in the Wurts or Fittig synthesis of 
hydrocarbons, bemene and petroleum ether exercise an unfavorable 
influence (60S). 

In the very complex reaction of the vulcanization of rubber, in 
which a large number of substances have a beneficial effect (104 and 
107), phenyl-hydrazine is a very marked negative catalyst.*® 

12. Water which so often acts as a positive catalyst, can some- 
times retard or even prevent reactions. 

Moist hydrogen reduces nickel oxide less rapidly than dry.*^ 

The decomposition of oxalic acid by hot concentrated sulphuric 
acid is impeded by the addition of very small amounts of water. The 
time of decomposition, imder the same conditions of heating, is more 
than trebled by the addition of 0.05% of water, while 1% of sulphur 
trioxide renders the reaction tumultuous.'* 

The presence of a little water retards the decomposition of diazo- 
acetic ester in alcoholic solution.*' 

Moisture retards the fixation of oxygen in the direct oxidation of 
unsaturated organic compoimds in the presence of metallic catalysts.*^ 

The presence of traces of water hinders the attack on metallic 
aluminum by fatty acids and by methyl, butyl, amyl, and benzyl 
alcohols as well as by various monophenols, ordinary phenol, the 
cresoles and a- and jg-naphthols.*' 

13. In chemical systems in which autocatalysis takes place (8), 
the presence of substances which form stable compounds with the 
catalysts engendered during the reaction, hinders their effect. Hence 
such substances are stabilizers, or negative catalysts. 

In the action of nitric acid on metals, various oxidising agents, 
hydrogen peroxide, potassiimi permanganate, and chloric acid are 
negative catalysts because they hinder the accumulation of nitrous 
fumes by oxidising them to nitric acid and thus preventing their ac- 
tion as positive catalysts. 

With regard to powders having organic nitrates as bases (powder 
B, nitrogylcerine, etc.), all substances, such as amyl alcohol and 
diphenylamine, which are capable of fixing, either as salts or as 
esters, the acid products engendered by the slow spontaneous denitri- 
fication of such powders and which hasten their decomposition, are 
stabilizers. 

" Pbacrbt, Jour. Soc. Chetn. Ind., 36, 424 (1917). 
*^ Sabatdeb and EsPOy CompL rend., 158, 668 (1914). 
>> Bbbdig and Frabvkbl, Berichte, 39, 1756 (1906). 

<• MnjjiB, Zeit. physik. Chem., 85, 129 (1913). Bbauns, Ibid., p. 170. 
Smamjum, Ibid., p. 211. 

M FoKXN, Zeit. anorff. Chem., 33, 1451 (1909). 

** SnjOMAK and Williams, /. 8oe. Chem. Ind., 37, 159 (1918). 



14 CATALYSIS IN ORGANIC CHEMISTRY 6 

14. Inversion of Reactions. According to circumstances, cat- 
alysts are frequently able to work in inverse directions. 

We have seen above (2) that platinum black thrown into hydro- 
gen peroxide, induces its rapid decomposition with separation of 
oxygen. Inversely, platiniun black serves to oxidise many substances, 
for example, alcohol which it transforms into aldehyde and acetic 
acid (244). It is now an oxidation catalyst and now a deoxidation 
catalyst. 

15. At about 350^, hydrogen and iodine vapor combine rapidly in 
contact with platinum sponge,*' and at the same temperature and 
with the same catalyst, hydrogen iodide is dissociated.'^ 

Finely divided metals such as nickel reduced from the oxide, 
readily add hydrogen to hydrogenizable substances at 180^; benzene 
is thus transformed into cyclohexane (446). On the contrary, the 
inverse effect is produced when cyclohexane vapor is passed over 
nickel at 300^; hydrogen is eliminated and benzene is regenerated 
(641). 

Reduced copper which is capable of hydrogenating aldehydes to 
alcohols at 180^ (522), dehydrogenates alcohols at 250^ to produce 
aldehydes (653). 

The direct hydrogenation of nitriles over nickel at 180** readily 
fiunishes primary amines (426) ; but inversely, nickel causes the de- 
composition of the amines at 350° into the nitriles and hydrogen 
(681). 

Platinum, nickel, and copper are thus catalysts of hydrogenation 
or of dehydrogenation as the case may be. 

16. Phenol vapor passed over thoria at 450**, is regularly dehy- 
drated to form phenyl oxide (786) ; but the same catalyst at the 
same temperature can bring about the splitting of phenyl oxide by 
water to regenerate phenol.'^ Hence thoria is at the same time a 
catalyst for hydration and for dehydration. 

17. It is the same way with strong mineral acids, such as sulphuric 
and hydrochloric, which are equally capable of bringing about the 
addition of water as in the saponification of esters (313), or its 
elimination as in esterification (749). 

18. Soluble ferments, such as emvlsine, which are in reality true 
catalysts, acting in homogeneous system, easily decompose gluco- 
sides by hydration and are also capable of synthesizing glucosides 
by dehydration. Thus galactose treated with emulsine in concen- 

«• CoBBNWiNDBR, Ann, Chim. Phy$. (3), 34» 77 (1852). 

ST HAUTBFBunJA, Cotnpt. rend., 64, 608 (1867). 

M Sabatdb, and Ebvil, BuU. 80c. Chim., (4), 15, 228 (1914). 



7 CATALYSIS IN GENERAL 24 

trated solution condenses by dehydration into galactobiose ; the 
latter, on the contrary, in dilute solution, is hycirated by the emulsine 
to regenerate the galactose.'* 

19. Reversible Reactions. In any reaction in which catalysts 
are able to activate the transformation in the two opposite directions, 
there results an equilibrium, the same limit being reached from either 
end. The catalyst only modifies the velocity of the opposing re- 
actions without essentially changing their character; consequently 
in reversible reactions, the location of the limit is not, in general, 
changed by the intervention of the catalyst, though the catalyst 
enormously shortens the time required to reach that limit. 

20. Lemoine has verified this for hydriodic acid which 
immediately reaches its limit of decomposition, 19% at 350^, in the 
presence of platinimi sponge. Without a catalyst, at the same tem- 
perature, under 2 atmospheres pressure, the limit was 18.6% but was 
not reached till after 250 to 300 ho\u-s.'<^ 

21. Berthelot arrived at the same conclusions with the esterifica- 
tion of alcohols by acetic acid. For equivalent amoimts of ethyl 
alcohol and acetic acid, the limit of 66.6% esterification is not 
attained at room temperature till after the lapse of several years of 
contact: on the contrary, in the presence of traces of hydrochloric 
or sulphuric acids, the identical limit is reached in a few hours. 

22. An immediate consequence of the foregoing is that, in rever- 
sible reactions, the location of the Umit is independent of the nature 
of the catalyst. This has been verified for the condensation of 
acetaldehyde. Whatever causes its polymerization into paraldehyde 
(hydrochloric acid, sulphur dioxide, oxalic acid, or zinc sulphate, 
etc.) always transforms the same proportion.*^ 

23. Velocity of Catalyzed Reactions. The presence of a cat- 
alyst greatly influences the velocity of reactions. It is in order to 
examine the effect of: 

1. Temperature, 

2. Pressure, 

3. Quantity of catalyst. 

24. Temperature. Temperature plays a capital r61e in many 
catalytic reactions, just as it does in most chemical changes. They 
do not take place except above a certain temperature; the direct 
hydrogenation of benzene in the presence of nickel hardly takes place 

>• BouBQXTiLOT and Aubbt, Compt. rend,, x63» 60 (1916). 
*^ LBMoms, Arm. Chim, Pkys. (5), 12, 145 (1877). 
*^ TuBBABA, Zeit. physik. Chem., 38, 605 (1901). 



26 CATALYSIS IN ORGANIC CHEMISTRY 8 

at all below 70^, while that of ethylene begms as low as 30^ (413) , 

and that of acetylene goes on at room temperature (423). \ 

The decomposition of alcohol into ethylene and water by blue 
oxide of tungsten commences only at about 250^ (709) ; the dehydra- 
tion of phenol to phenyl oxide by thoria requires a temperature above « 
400° (786). 

25. Elevation of the temperature also increases greatly the 
velocity of reactions: in fact it is found that, in a large number of . 
cases, this velocity is doubled when the temperature is raised 10°. \ 
Reactions in which catalysts intervene do not escape the general rule i 
and are greatly accelerated by elevation of temperature which is con- | 
sequently favorable, so long as it does not greatly change the mech- j 
anism of the reaction — which, however, frequently happens. Thus | 
catalytic hydrogenation is frequently replaced, above a certain tem- | 
perature, by its reverse, catalytic dehydrogenation. I 

26. For example in the hydrogenation of benzene over nickel, the 
velocity of the formation of cyclohexane increases rapidly from 70°, 
where it is very slow, up to 180-200°, the most favorable tempera- 
ture. From there on it decreases as 300° is approached, at which 
this reaction no longer takes place, cyclohexane being, on the con- 
trary, decomposed into benzene and hydrogen or even into benzene 
and methane according to the equation: 

3C.H,, — 2C.He + 6CH^, 

this latter reaction becoming more important as the temperature is 
raised.*' 

27. In the hydrogenation of acetylene which takes place without 
complications at room temperature (423), elevation of temperature 
tends to introduce, by the side of the transformation into ethane, the 
condensation of acetylene into more complex molecules even to the 
formation of solid carbonaceous deposits (924). 

28. In the dehydration of primary alcohols by contact with anhy- 
drous oxides, elevation of temperature tends to introduce or to accel- 
erate the reaction of dehydrogenation whereby aldehydes or com- 
pounds produced from them are formed (709). 

29. Thus, by a judicious choice of reaction temperature, it is fre- 
quently possible to obtain, at will, various degrees of combination. 
For example, in the hydrogenation of anthracene over nickel, at 180°, 
perhydroanthracene, Ci4H24, is obtained, along with the dodecahydro- ; 
at 200° the octohydro- is prepared and at 260°, the tetrahydro-." 

s> Sabatub, and Sbndbbbns, Arm. Chitn. Phys. (8), 4, 334 (1905). 
M GcoGHor, Ann. Chim. Phys. (8) za, 468 (1907). 



9 CATALYSIS IN GENERAL 34 

30. Pressure. Increase of pressure can scarcely have any con- 
siderable effect except in gaseous systems or in heterogeneous systems 
having a gaseous phase. In such cases, it can be foreseen that it 
will have a beneficial effect in those cases in which the number of 
molecules is diminished in the reaction.*^ This is the case in the 
hydrogenation of compounds containing an ethylene bond and prac- 
tical use is made of it in the hydrogenation of liquid fats (956) . 

Likewise in the direct hydrogenation of phenol by nickel, in the 
liquid system aroimd 150^, the formation of cyclohexanol is extremely 
slow in hydrogen at ordinary pressure, but, on the contrary, is rapid 
ahd complete imder 15 atmospheres.*^ 

31. On the contrary, molecular decompositions such as the de- 
hydrogenation of alcohols into aldehydes or ketones, in contact with 
finely divided copper, are favored by a lowering of the pressure, which 
diminishes also the reverse reaction (653). 

32. Quantity of Catalyst. We must at once distinguish between 
the two cases, whether the catalyst acts in homogeneous or hetero- 
geneous systems. 

In homogeneous systems, in which the catalyst remains in intimate 
mixture with the components of the reaction, it acts by its mass and 
its action increases with its concentration. 

In the manufacture of, sulphuric acid by the lead chamber process, 
in which oxides of nitrogen serve as the catalyst, the velocity is pro- 
portional to their concentration up to a certain limit. 

In the inversion of sugar solutions by mineral acids (324), and 
in the saponification of esters by the same agents (313) , the active 
agents in the catalysis are the free hydrogen ions arising from the 
electrolytic dissociation of the acids and the velocity of the reaction 
is proportional to the concentration of these ions. 

In the catalytic decomposition of hydrogen peroxide by small 
amounts of alkali, the rapidity of the decomposition is nearly pro- 
portional to the concentration of the alkali.** 

33. It is the same way with certain solid catalysts, iodine in the 
chlorination or organic compounds (278), and anhydrous aluminum 
chloride in the Friedel and Crafts reaction (883), which do not act 
till they have been dissolved in the liquids of the system to be trans- 
formed and then are comparable to liquid catalysts, with activity 
proportional to their concentration. 

34. Heterogeneous systems are much more frequently met with: 

•« Dabzins, Bull. 8oc. Chim. (4), 15, 588 (1914). 

s* Bbochst, Ibid. (4), 15, 554 (1914). 

M I^Monoi^ Compt. rend,, 161, 47 (1915). 



35 CATALYSIS IN OEGANIC CHEMISTRY 10 

the catalyst in such is a solid phase in a liquid or gaseous medium 
and exercises its useful power only on its surface. The action, at first 
sight, depends on the extent of the surface, or at least on the mass 
of an extremely thin layer. A layer of silver 0.0002 mm. thick, de- 
posited on glass, causes a very rapid decomposition of hydrogen 
peroxide.*^ 

35. Solid catalysts are more active the greater their surface, and, 
for the same weight, the finer their grains; but there is, by no means, 
a rigorous proportionality between the activity and the extent of 
surface. 

In liquids, convection currents which bring the material to be 
transformed into more or less perfect contact with the catalysts, 
have an important influence on the rate of the reaction, but one dif- 
ficult to estimate. If the mixture is kept perfectly homogeneous, the 
active surface of a given catalyst, made up of grains of the same size, 
should be proportional to the number of grains, that is to say, to the 
total mass, but should increase very rapidly as the grains become 
smaller. 

For a solid catalyst acting in a gaseous system, the incessant and 
very rapid movement of the gas particles is sufficient to assure the 
homogeneity of the system. The activity of the catalyst, if it is in 
a very thin layer, is proportional to the area of this layer. If the 
layer is thick, not only the surface particles act but also those within, 
the effect of the interior particles being more important, in propor- 
tion as the grains which compose the catalytic material are lifter 
and less agglomerated. With a solid in a fine powder, which is 
readily penetrated by the gas, the useful surface is extremely large 
as compared with the exterior surface of the layer. The state of 
division of a solid catalyst is a matter of prime importance. The 
catalytic power of nickel in sheets or even in thin foil is quite minute 
and of no practical value, while it is highly developed in the finely 
divided nickel which is obtained by reducing nickel oxide by hydro- 
gen, below red heat, and particularly so when the oxide obtained by 
dehydration of nickel hydroxide is itself finely divided. 

From this point of view, there are great differences in various 
catalysts according to the conditions of their preparation (see 
Chapter II). 

S7 Lkmoinb, Ibid,, 155, 15 (1912). 



CHAPTER II 
ON CATALYSTS 

36. As chemistry has developed, the number of catalytic phe- 
nomena has increased enormously and it has been recognized that 
the r61e of catalyst is played, not by a few bodies only but by a mul- 
titude of substances of every sortr 

37. Solvents. The definition proposed by Ostwald, "A catalyst 
is a sub8ta:nce which, without appearing in the final product, influ- 
ences the velocity of a reaction/* leads us to consider an infinite num- 
ber of substances as catalysts. Solvents, whatever their nature, are 
catalysts since they do not appear in the equation of the reaction 
which they cause to take place. 

In the absence of a liquid which dissolves them and thus realizes 
the contact which is indispensable to combination, solid substances 
which have no appreciable vapor pressure in the cold, are incapable 
of reacting with each other. 

Dry crystals of oxalic acid and chromic anhydride can be mixed 
cold without any chemical change, but the addition of water which 
establishes perfect contact between the two substances, inmiediately 
starts the oxidation of the oxalic acid at the expense of the chromic 
anhydride. The water may be recovered completely and imchanged 
by the reaction. It acts as a catalyst. 

38. The nature of the solvent can change greatly the velocity of 
reactions which take place in it, and furthermore, the influence which 
it exercises is absolutely special in each case. 

Water is a true catalyst in the decomposition of hydrogen 
peroxide.^ 

In the fixation of hydrogen, by colloidal palladium, upon the acet- 
ylene triple bond, the. solvent has an important influence of its own.' 

The combination of triethyUamine with ethyl iodide to form 
tetraethyl-ammonium iodide at 100^, is 203 times as rapid in ethyl 
alcohol, 718 times in acetophenone, and 742 times in benzyl alcohol, 
as it is in hexane* 

^ LiMomi, Compt. rend^ 155, 9 (1912). 

* Zal'kikd and Pibghikot, Jour. Ruman Phys. Chem. 80c., 46, 1527 (1914), 
C. A^ 9, 2067. 

• MiNBOHirrsiN, ZeU. phys. Chem^ z, 611 (1887); 6, 41 (1890). 

11 



39 CATALYSIS IN ORGANIC CHEMISTRY 12 

39. In reversible reactions, the limit will not be altered by a 
change of solvent if this does not react in any way with either the 
reactants or the products: otherwise the limit will be modified. For 
example, in reactions between electrolytes, brought about in alcohol 
or in water, electrolytic dissociation is of great influence in case water 
is the solvent. 

40. Solvents are not commonly classed with true catalysts as this 
designation is usually reserved for those substances which act in 
small concentration and of which a small quantity is able to cause 
large quantities of other materials to react. 

DIVERSE SUBSTANCES CAN ACT AS 

CATALYSTS 

41. The number of substances capable of acting as catalysts, is 
already very large and continues to increase with the progress of 
chemistry. 

We find in this class the most varied materials: elements, oxides, 
mineral acids, bases, metallic chlorides, bromides, iodides, fluorides 
and oxygen salts, ammonia and its derivatives, and diverse organic 
compounds. But, particularly for solids, the catalytic activity can 
vary greatly according to their origin, either if they can exist in dis- 
tinct molecular forms, or, more frequently, if they present them- 
selves in different states of sub-division (32). 

ELEMENTS AS CATALYSTS 

42. Elements which are of themselves true catalysts, maintaining 
themselves imchanged during the course of the reactions which they 
provoke, are quite nimierous and it is convenient to consider along 
with them those which pass immediately into compounds which act 
as catalysts. This is the case with chlorine, bromine,' iodine, tel- 
lurium, sulphur, and phosphorus among the non-metals and tin, 
antimony, and thallium among the metals. 

43. Chlorine and Bromine. These probably act by the im- 
mediate formation of the hydro-acids, to transform aldehydes into 
the polymeric paraldehydes. 

44. Iodine. Iodine acts in the same way in the same reactions. 
It is frequently employed in chlorinations, and acts then by trans- 
forming itself into the trichloride which is the real factor in the ca- 
talysis. It permits the direct sulphuration of aromatic amines with 
the elimination of hydrogen sulphide (296). It can aid in causing 



13 ON CATALYSTS 49 

the condensation of aromatic amines with naphthols (790) . It serves 
also to facilitate the reaction in the preparation of the organo- 
magnesium halides of the Grignard reagent, when it is desired to pre- 
pare these from chlorides or bromides (302). 

45. Sulphur and Tellurium. Employed as carriers in chlorina- 
tion, they certainly act in consequence of the initial formation of an 
equivalent amount of the chlorides. Tellurium has been proposed as 
an agent in direct oxidation (251). 

46. Phosphorus. Red phosphorus has been mentioned as a 
catalyst for the dehydration of alcohols above 200'' (699). The 
chief factor in this catalysis appears to us to be the small quantity 
of acids of phosphorus which exist in the phosphorus or which are 
produced from it by the oxidising effect of the alcohol. 

47. Antimony, Tin and Thallium. Their use in chlorination is 
based on the primary formation of their perchlorides. 

48. Carbon. All the porous forms of carbon have been employed 
as catalysts. 

The carbonaceous mass obtained by calcining blood With potas- 
sium carbonate is a good catalyst for chlorination.'* 

Ardmal charcoal is a mediocre catalyst for the dehydration of 
alcohols (699) , but is efficient in the preparation of carbonyl chloride 
from carbon monoxide and chlorine (282). 

Coke may serve as an oxidation catalyst (258). 

Wood charcoal, or baker's charcoal possesses considerable absorb- 
ing power for many gases, the consequence of which is frequently the 
production of special reactions. Carbon saturated with oxygen can 
produce oxidations: ethyl alcohol is changed to acetic acid. Ethyl- 
enic hydrocarbons are partially burned.' 

Carbon saturated with chlorine enables us to chlorinate sulphur 
dioxide in the cold as well as hydrogen.^ 

Baker's charcoal catalyzes the decomposition of primary alcohols 
above 380^, giving, at the same time, aldehydes and ethylene hydro- 
carbons (679). It is frequently employed for the preparation of 
carbonyl chloride (282). 

49. The porosity of the carbon has a great influence. Thus in 
the case of 30 volimie hydrogen peroxide of which the half decompo- 
sition at 17^ required 240 hours, the addition of 5% of cocoanut 
charcoal (in pieces 1 to 2 mm. in size) reduced this time to 15.4 hours, 
while the same weight of charcoal from the black alder lowered it 

^ DAMOiSBAn, Compt. rend,, 83, 60 (1S76). 
> CAunar, Ibid., 64, 1246 (1867). 
• Mblbins, Ibid., 76. ^ (1873). 



50 CATALYSIS IN ORGANIClCHEMISTRY 14 

only to 212 hours. Sugar charcoal falls between these two as an 
activator/ 

60. Sodium brings about the isomerization of unsaturated hydro- 
carbons, e. g,, diethylallene into diethylallylene (192). It polymerizes 
isoprene (213) as well as acetonitrile (231). 

51. Magnesiiun. Magnesium powder has been mentioned as 
very active in decomposing hydrocarbons at 600® (918). 

Aluminum. The same property has been claimed for aluminum 
which has been proposed as a chlorination catalyst also because it 
changes immediately to the chloride. Aluminum turnings are only 
a mediocre catalyst for oxidation (255). 

52. Manganese. Powdered manganese is a poor catalyst for 
oxidations (255) but is an excellent aid to bromination (292). 

Zinc turnings, at 100®, can cause the condensation of acetaldehyde 
into aldol or into crotonic aldehyde (219) . The same metal acts as 
a dehydrogenating agent on alcohols at 600-50®, temperatures at 
which the metal is melted, a condition xmfavorable to cataljrtic 
action (670). 

53. Nickel. Employed in the state of extremely fine division, 
as is obtained by the reduction of the oxides by hydrogen or carbon 
monoxide, nickel is a marvelous catalyst, the manifold activity of 
which has been established by the investigations of Sabatier and 
Senderens, beginning in 1879. It is specially suitable for the direct 
hydrogenation of volatile organic compounds, but it is equally 
capable of producing dehydrogenations and decompositions whether 
they are followed by molecular condensations or not. Chapters VIII, 
IX and XII are devoted to catalytic reactions effected by nickel. 

54. The metal in sheet or even in thin foil possesses only slight 
activity. Catalytic nickel should be prepared by reducing the oxide, 
and as the metal so produced is readily oxidised and frequently pyro- 
phoric, it is generally best to carry out the reduction in the same tube 
in which the catalysis is to be effected. However this is not abso- 
lutely necessary, if the precaution is taken to cool the reduced metal 
perfectly in the current of hydrogen, or better still in a current of 
pure nitrogen." The metal so prepared can be preserved in a well- 

7 Lkmoinb, Ibid., x6a, 725 (1916). 

* When freshly prepared highly active nickel is exposed freely to the air, 
a rapid heating takes place that considerably impairs its catalytic activity. The 
change which takes place in the nickel is brought about and augmented by the 
heat produced by the catalytic oxidation of the hydrogen occluded and surround- 
ing the nickel when it comes in contact with an excess of oxygen from the air. 
Similar oxidation of hydrogen is well known in the presence of oatalsrtic pal- 
ladium or platinum. In the case of catalytic nickel, however, the heat thus 



16 ON CATALYSTS 67 

stoppered bottle for quite a long time without considerable alteration. 

65. The activity of the reduced nickel varies greatly according 
to the nature of the oxide and the manner of reduction. The metal 
is more active, the greater its surface; and the lighter the oxide and 
the lower the reduction temperature, the greater is this surface. 

Nickel reduced' at a bright red is no longer pyrophoric and 
possesses a considerably reduced catalytic power. 

On the contrary, that which comes from the hydroxide precipitated 
from the nitrate, dried and reduced around 260^, has an excessive 
activity along with maximum alterability. It can be compared to 
a spirited horse, delicate, difficult to control, and incapable of 
sustained work. 

Applied to phenol, it passes by cyclohexanol and produces cyclo- 
hexane to a large extent. It tends to produce molecular dislocations 
in bodies submitted to catalysis. 

66. An excellent quality of nickel is obtained by dissolving the 
commercial cubes in pure nitric acid (free from hydrochloric), calcin- 
ing the nitrate at a dull red and reducing at about 300^ the oxide 
thus obtained. Such a nickel can do all kinds of work and maintains 
its activity for a long time. 

It has been stated that nickel prepared above 360^ is incapable 
of hydrogenating the aromatic nucleus,* but Sabatier and Espil have 
shown that this ability is still possessed by a nickel prepared at 700^ 
even when it is kept at this temperature for several hours, but not 
by nickel prepared by reduction above 750® or heated for some time 
at 750^^• 

67. Cobalt. Finely divided cobalt, such as is obtained by the 
reduction of the oxide by hydrogen, can be employed as a catalyst 
for the same purposes as nickel, but is less useful as it is less active, 



generated in the presence of an exceas of oxygen, or air, produces an oxidation 
of the catalyzer to an extent that lessens or destroys its activity. A number of 
experiments were made in which freshly prepared nickel catalyzer still in the 
presence of hydrogen was subjected to the action of a Geryk pump which ex« 
hausted practically all of the excess hydrogen gas. In different experiments the 
catalyzer was then, while cold, allowed slowly to come in contact with carbon 
dioxide, nitrogen, and air. The catalyzers so formed were active and retained 
their activity reasonably well. In case air was admitted to the vacuum vessel 
containing the catalyzer, it was introduced veiy slowly so that any oxidation 
would be so slight as not to increase the temperature sufficiently to produce 
cumulative oxidation. — M. H. Ittkeb. 

* Daszens, CompL rend., 139, 869 (1004); Bbunbl, Arm. Chim. Phys. (8), 
6, 205 (1903). 

^^ Sabatob and Epsn., BmU. 80c. Chim. (4), 15, 779 (1914). 



58 CATALYSIS IN ORGANIC CHEMISTRY 16 

and as the reduction of its oxide requires a higher temperature, in 
fact above dOO**. 

58. Iron. Reduced iron can replace nickel in quite a large 
number of cases, but disadvantages, like those mentioned for cobalt, 
are more serious, the oxides being still more difficult to reduce. 
Between 400^ and 450^, it is necessary to prolong the action of the 
hydrogen for six or seven hours to obtain complete reduction. 
Furthermore, the metal reduced at this high temperature is no longer 
pyrophoric and retains only mediocre activity. However, pulverized 
iron is a useful catalyst for decompositions accomplished at a low red 
heat (932). 

Iron has been mentioned as a chlorination catalyst, but in that 
case it serves only to form iron chloride which is the real catalyst. 

59. Copper. Copper, reduced from its oxide by hydrogen, con- 
stitutes, on account of its ease of preparation, the low temperature 
at which the oxide can be reduced, below 180^, and the regularity 
of its action, a valuable catalys£ for certain reactions, but it is not 
capable of effecting all kinds. Its activity also varies considerably 
according to the method of production. The black oxide of copper, 
prepared by roasting the metal or by calcining the nitrate at a bright 
red, furnishes by reduction, with incandescence, a clear red, very 
compact metal with low catalytic power. By reducing with a slow 
current of hydrogen (to avoid incandescence) at about 200^, the 
tetracupric hydroxide — such as is precipitated from boiling cupric 
salt solutions by alkalies — a very light violet colored metal is 
obtained with much greater catalytic activity. The very fine copper 
powder which is commercially prepared for imitation gilding, can 
frequently be used: it is only necessary to free it from grease by 
washing with ethier or ligroine. 

This latter has been used to facilitate several of the reactions of 
aromatic diazonium salts in which nitrogen is eliminated (606). It 
is efficient in causing the production of phenyl oxide by the action of 
brombenzene on sodiiun phenylate (904). 

Copper in spirals, or in gauze, has been employed, with advantage, 
in the catalytic oxidation of alcohols, ethers, hydrocarbons, and 
amines (254). 

60. Silver. Silver powder is an excellent oxidation catalyst (253) . 
Inversely, it causes the rapid decomposition of hydrogen peroxide, 
transforming itself into the oxide Ag^Og which continues the 
catalysis." 

61. Platinum. Platinum is one of the longest known catalysts. 

" Bbbthilot, BvU. 8oc. Chim, (2), 34* 135 (1880). 



17 ON CATALYSTS 63 

Not oxidisable in the air at any temperature, it is a powerful catalyst 
for oxidation or for hydrogenation, especially when it is finely divided 
and presents a large surface. This is the condition realized in 
platinum sponge, a porous material obtained by calcining ammonium 
chlorplatinate, and even better in platinum black and in colloidal 
platinum, which can be mixed intimately with liquids submitted to 
catalysis (67). 

62. Platinum black can be prepared either by reducing acid 
solutions of platinic chloride^' by zinc, or better by magnesium, or 
by treating the platinum chloride with alcohol and alkalies,^* or by 
reducing the platinum! salt with sodium formate,^^ or with sodium tar- 
trate, or even with glucose in alkaline solution, or by glycerine and 
potash.^' 

An excellent method is that of Loew: 35 cc. formalin is added to 
25 g. platiniun chloride dissolved in 30 cc. water and then, little by 
little, while cooling 25 g. caustic soda dissolved in its own weight of 
water. After twelve hours it is filtered off and washed. A spongy 
mass is thus obtained which is dried in the cold over sulphuric acid.^* 

Platinum black always retains traces of substances with which 
it has been in contact during its preparation. Blacks prepared in 
alkaline solution are more active than those from acid solution. 

63. According to Lemoine the grains of platinum black, of which 
the diameter is about 0.1 mm., are much more active than those of 
the sponge for the same area. With a specimen of hydrogen peroxide 
which, without catalyst, required ten days for half decomposition, 
this time was reduced by platiniun black to 0.00013 hour and with 
the same surface of the sponge only to 0.2 horn*. The black possesses 
a specific activity which is, without doubt, due to less molecular 
condensation and which disappears when it is heated to 400 to 500^.^^ 

This weakening by heating is progressive. Thus platinum black 
is not sensibly altered as a hydrogenation catalyst when heated below 
300^ and still retains its power to transform limonene into menthane 
by the fixation of 2H2. If it is heated to 430^, it is considerably 
weakened and can add only H, to the external double bond, giving 
carvomenthene. Heated to 500**, it loses all activity .^^ 

1* BoBiTGBB, /. Prakt. Chem. (2), a, 137 (1870). 
i> Zdsb, Pogg. Ann., 9, 632 (1827). 
2« DODBBBINSB, Ibtd^ 2B, 181 (1833). 

^<( ZDBAWKowrrcH, Bull 8oc. Chim. (2), as, 108 (1876). 

^* Ix»w, Berichie, a3, 289 (1890). Improved directions for this important 
preparation are given by WnxsTATiBB and WA]j>scHMiDT-LBrrz in Benchie, 54, 
121 (1921).— E. E. R. 

^^ Iamoinb, Compt. rend^ z6a, 657 (1916). 

i« Vaton, Ibid., Z58, 409 (1914). 



64 CATALYSIS IN ORGANIC CHEMISTRY 18 

Compact platinum in foil or wire has a certain activity, at leaBt, if 
it has been previously heated above 50^. A heated platmum spiral 
introduced into a mixture of alcohol vapor and air or oxygen, causes 
the formation of aldehyde and the incandescence which results from 
the heat liberated in the oxidation, maintains itself indefinitely so 
long as the mixture is renewed: this is the lamp vnthout flame}^ 

64. Rhodiimi, Rutheniimi, Iridium, and Osmiimi. Employed 
in the form of the pulverulent black, or as sponge, these metals act 
in the same manner as platinum, at least as regards reactions of oxida- 
tion or of decomposition, but they are less active in hydrogenation 
(580). 

Rhodium or iridium black decomposes, in the cold, formic acid 
into hydrogen and carbon dioxide (822). In contact with alcohol 
and caustic soda, hydrogen is evolved with the formation of sodixmi 
acetate.*® 

65. Palladium. Palladium exhibits the property of absorbing 
very large quantities of hydrogen, even up to 930 times its own 
volume.*^ Palladium thus saturated with hydrogen can effect a large 
number of hydrogenations. But the metal can serve also as a tem- 
porary support for hydrogen, that is to say, as a hydrogenation cat- 
alyst, in the form of sponge or black (573) , and can be employed as 
a catalyst for dehydrogenation (669), for decomposition (624), or 
for polymerization (212). 

66. Gold. Gold, when finely divided, has catalytic properties 
resembling those of silver. 

67. Colloidal metals. The catalytic activity of metals, being in 
direct relation to the extent of their surfaces, consequently to the 
minuteness of their particles, should reach its maximum in the col- 
loidal state. As the chemical alterability of the metals is also inten- 
sified by their extreme subdivision, it would hardly be expected that 
any could be practically used in this state except those not oxidiaable 
in the cold, such as platinum, palladium, gold and silver. 

68. Bredig *' has described a simple method for preparing colloidal 
metals: an electric arc is made to play between two wires of the 
metal under pure water. A sort of nebulosity is observed which 
becomes darker and darker till it is soon so opaque that the spark 

^» HoFMANN, Armalen, 145, 358 (1868). 

'0 Saintb-Claire-Devillb and Debrat, Compt, rend,, 78, 1782 (1874). 

" Graham, PhU. Mag,, (4), 3a, 401 and 503 (1866); 36, 63 (1868). Proc, 
Roy, Soc, 15, 223, 502 (1867); 16, 429 (1868); 17, 212 and 500 (1869). Compt. 
rend., 63, 471 (1866) and 68, 101 (1869). 

*> Bbediq, Zeit. physik. Chem., 31, 258 (1899) ; 37, 1, 323 (1901) ; BerichU, 
37> 798 (1904); ZeU. Elektroch., 14, 51 (1908). 



19 ON CATALYSTS 71 

can not be seen. Solutions thus obtained can be preserved for a long 
time and contain 0.09 to 0.02 g. gold per liter and a less amount of 
palladium or platinum: the number of particles in such a solution 
may reach as high as a billion per cubic millimeter. 

69. Unfortimately such solutions are unstable in the presence of 
various substances. The presence of suitable organic materials gives 
them stability and Paal has foimd that egg albimien has this effect. 
He dissolves 15 parts of caustic soda in 500 parts of water, adds 100 
parts egg albumen and warms on the water bath till solution is nearly 
complete. It is acidulated with sulphuric acid and the precipitate 
filtered off. The solution is neutralized with soda, evaporated on 
the water bath to a small volume and again acidulated with sulphuric 
acid. 

The filtered solution is dialyzed to separate the sodium sulphate. 
The liquid remaining in the dialyzer is treated warm with baryta 
water which precipitates the remaining sulphate ions. The filtered 
solution is evaporated on the water bath and several volumes of 
alcohol added, which precipitates white flakes which Paal has named 
lysalbinic acid. When dry, this is a white powder, soluble in water 
and nearly insoluble in alcohol: its weight is about one-fourth that 
of the albumen. 

One gram of the above product is dissolved in 30 cc. water and 
made alkaline with a slight excess of soda, 2 g. platinum chloride dis- 
solved in a little water is added and then a slight excess of hydrazine 
hydrate. The solution turns dark and a gas is evolved: after five 
hours it is dialyzed to eliminate electrolytes, carefully evaporated on 
the water bath and dried in vacuum. Brilliant black scales are 
obtained which dissolve in water to form a black opaque solution: 
this is colloidal platinum. 

Colloidal palladium is prepared in an analogous manner.'* 

Solutions of these are very stable and can even be heated for a 
long time .without change. 

70. In this way colloidal solutions can be prepared of silver, gold, 
copper, osmium, and iridiimi, all decomposing hydrogen peroxide with 
extreme energy. Traces of osmium produce this effect.'^ 

71. Skita prepared a colloidal palladium hydroxide, for use as a 
hydrogenation catalyst, by heating to boiling a solution of palladium 
chloride, PdCl,, with soda and a little gum arabic. The solution is 

^ Paal, Berichte, 35, 2195 (1902). Paal and Ambergbb, Ibid., 37, 126 (1904) 
and 38, 1398 (1905). Kelbeb and Schwartz, Ibid., 45, 1946 (1912). Skita and 
MxTiB, Ibid., 45> 3579 (1912). 

** Paal and AMBEBon, Berichte, 40, 2201 (1907). Paal;, Bibhleb and Sistbb, 
Ibid., 50, 722 (1917). 



72 CATALYSIS IN ORGANIC CHEMISTRY 20 

dialyzed till neither silver nitrate nor baryta water gives a test out- 
side. The solution, evaporated to dryness in a vacuum, gives brown 
scales of colloidal palladium hydroxide, insoluble in cold water but 
soluble in water containing traces of acid or alkali. 

Another method of preparing colloidal palladium, given by the 
same author, is to pass a current of hydrogen through a warm solu- 
tion of palladous chloride and gum arable. 

A colloidal platinum hydroxide, analogous to that of palladium, 
is obtained by treating a boiling solution of potassium chlorplatinate 
with the theoretical amount of decinormal soda and adding gum 
arable. The brown solution by dialysis, and evaporation in vacuum, 
g^ves a black solid, insoluble in water but made soluble by a trace 
of alkali. 

The solutions so obtained can be neutralized, dialyzed and evap- 
orated in vacuum: the black scales so obtained dissolve readily in 
water and can be employed for hydrogenations in acid media (561). 
The solutions are not coagulated by boiling with acetic acid, nor by 
heating with water under pressure. 

In another process, called the germ method, the same chemist adds 
to a solution of platinum chloride, PtCl4, containing gum arable, a 
trace of a previously prepared colloidal platinum in solution, and 
submits the liquid to the action of compressed hydrogen, by which 
means a colloidal solution of the metal is obtained.'^ 

72. Among colloidal metals, the maximmn activity for oxidations 
belongs to platinimi, osmium being only slightly active: ^* for hydro- 
genations, silver and osmium are much inferior to platinum and 
particularly to palladium; gold and copper produce no effect.'^ 

OXIDES AS CATALYSTS 

73. Water. Water appears frequently as a positive catalyst: 
quite a large number of reactions are not readily carried out except 
in the presence of traces of moisture. Oxidations are generally more 
difficult to realize by means of oxygen rigorously dried.^* A mixture 
of absolutely dry carbon monoxide and oxygen can not be made to 
explode. A flame of carbon monoxide is extinguished in perfectly 
dry air." Carbon and even phosphorus refuse to bum in perfectly 

*« SxTTA, Berichie, 45> 3312 (1912). 

s« Paal, BerichU, 49> 548 (1916). 

*7 Paal and Gbbum, Berichte, 40, 2209 (1907). 

*> Dixon, Proe. Roy. 8oc^ 37> ^ (1884). 

*• TBAT7Bl^ BerichU, z8, 1890 (1885). 



21 ON CATALYSTS 76 

dry oxygen.*® Hydrogen and oxygen thoroughly dried do not com- 
bine up to 1000^. Ammonia and hydrogen chloride when rigorously 
freed from moistiu-e do not form any solid ammonium chloride and, 
conversely, thoroughly dry ammonium chloride can be volatilized 
without decomposition and the density of its vapor is then normal.*^ 

A trace of moistiu*e is suj£cient to cause the transformation of 
vitreous arsenic trioxide into its octahedral isomer (porcelain like) .** 

Absolutely dry fluorine does not attack glass (Moissan). 

This beneficial catalytic effect of water is quite exceptional in 
organic reactions, but we may mention that in the catalytic oxidation 
of methyl alcohol vapors by a platinum spiral, the presence of water 
favors tiie production of formaldehyde. With absolute methyl alco- 
hol, incandescence is not produced unless the spiral has an initial 
temperature of at least 400^, while with 20% of water in the alcohol, 
175** is sufficient.** 

74. Sulphiu: Dioxide. Small amounts of this gas are sufficient to 
cause the polymerization of acetaldehyde into paraldehyde or 
metaldehyde (482). 

75. Anhydroua Metallic Oxides. Manganese dioxide rapidly 
decomposes hydrogen peroxide, without itself being altered. The 
same is true of the yellow oxide of lead in alkaline solution. Cuprous 
oxide is an active catalyst for the decomposition of diazoniimi salts 
(606). 

The studies that have been made in commercializing the contact 
process for sulphuric acid, discovered in 1831 (4), have shown that 
various finely divided metallic oxides may be substituted for the 
platinum. As early as 1852, Wohler and Mahla suggested for this 
purpose, oxides of iron, chromium and copper; and P^rie, Plattner, 
and Reich advised the use of pulverized silica.*^ In 1854, Tom- 
thwaite proposed manganese oxide. 

The application of anhydrous metallic oxides to the catalytic 
oxidation of volatile organic compounds was proposed anew in 1906 
by Sabatier and Mailhe, who mentioned specially the oxides of copper, 
nickel, cobalt, chromium, manganese and uranium (260). Matignon 
and Trannoy made the same suggestion (260). 

Several anhydrous metallic oxides, particularly alumina, thoria, 
blue oxide of tungsten, titania and zirconia, etc., are endowed with 

^ Bajoe, J. Chem. 8oc., 47, 349 (1886). 
*^ Baxbk, Ibid., 65, 611 (1804). 
» WiNXLB, /. pr. Chem. (2), 32, 247 (1885). 
•> Tbillat, BnU. 80c. Chim., (3), ag* 35 (1903). 

^ Silica gel has been found by Patrick to be an excellent catalyst for the 
oxidation of nitric oxide by oxygen. — E. E. R. 



76 CATALYSIS IN ORGANIC CHEMISTRY 22 

important catalytic activity towards alcohols, which they can decom- 
pose into misaturated hydrocarbons (701). They can catalyze the 
synthesis of thiols (743), ammes (732), ethers or phenol ethers (786 
and 789) and esters (762). These oxides and manganese oxide, 
employed as catalysts with acids produce symmetrical ketones (837) , 
mixed ketones (847), aldehydes (851) and decompose esters (858). 
They can also bring about the isomerization or polymerization of 
unsaturated hydrocarbons (211). 

76. The catalytic power of these various oxides is very variable, 
according to the method of preparation. 

Catalysis being a matter of surface, the amorphous oxides prepared 
from precipitated hydroxides, dehydrated at low temperatures, are 
much more active than crystallized oxides or those that have been 
sintered together by calcination at a red heat. 

These latter possess, for equal mass, a much smaller surface and 
are frequently, without doubt, in an advanced stage of molecular 
condensation. This is particularly true of the oxides of the metals 
of small atomic weight, aluminum, iron, silicon, chromium, etc. The 
action of acids has long shown such differences. 

77. Amorphous alumina, obtained by dehydrating the hydroxide 
below 400^, dissolves readily in mineral acids and is an active catalyst 
for alcohols, while crystallized alumina and amorphous alumina cal- 
cined at a bright red, are insoluble in acids and have almost no 
catalytic power for alcohols. 

Analogous differences are observed with the different varieties of 
silica, though, for the decomposition of hydrogen peroxide, silica cal- 
cined at red heat is more active than the dried silica.'* 

Ferric oxide prepared by dehydrating the precipitated hydroxide 
below 350^, is a much more powerful catalyst for alcohols than that 
obtained at a red heat.'* 

It is the same with regard to hydrogen peroxide of which the 
former decomposes 50% in 10 seconds, while the latter requires 1550 
seconds. 

78. Furthermore, the very nature of the catalyst is modified by 
these changes of constitution of the oxides. 

The seaquioxide of chromium, prepared by dehydrating the blue 
precipitated hydroxide, gives with ethyl alcohol 42 cc. gas per minute 
containing 91% of ethylene, while, after calcination at 500^, the same 
oxide furnishes only 2.8 cc. gas with 40% ethylene. The oxide pre- 

s« Lbmoinb, Compt, rend,, x6a, 702 (1916). 

** Sabatisb and Mau^b, Arm. Chim. Phys,, (8), ao, 313 (1910). 



23 ON CATALYSTS 81 

pared by the explosion of ammonium bichromate and, consequently 
formed with incandescence, gives 1.2 cc. gas, with 38% ethylene.'^ 

The crystallized oxide gives no gas at all at 350^, and 400^ must 
be reached to obtain 2 cc. which is then nearly pure hydrogen. The 
catalytic function is modified at the same time tiiat it is weakened.*" 

Analogous variations have been observed with silica and alumina, 
both in the intensity and in the direction of the decomposition,'* and 
a relation has been noted between the catalytic activity of alumina 
and its solubility in acids.^® 

79. Thoria, on the contrary, does not present this inconvenience 
and its activity is not sensibly diminished when it is calcined at a 
red heat: it appears that such a heavy molecule can not suffer 
important polymolecular condensations. 

80. Nickel oxide and especially nickel suboxide, which results 
from the incomplete reduction of the monoxide, have been regarded 
by some chemists as the best catalysts for carrying out the hydro- 
genation of organic compounds in a liquid medium. At least as 
active as reduced nickel, they have the advantage of being less alter- 
able and consequently of retaining their catalytic activity longer 
(584) . The researches of Sabatier and Espil have indeed established 
the existence of a suboxide, apparently Ni40, which is the first step 
in the reduction of the monoxide, but they have shown that this sub- 
oxide, while it is being formed, is partially reduced to the metal and 
it is this latter which is the sole factor in the hydrogenations that 
have been attributed to the oxide.*^ 

The same reservations should be applied to the oxide of osmium, 
which has been proposed as a hydrogenation catalyst (583) and 
which, doubtless, serves only as a source of finely divided osmium.** 

MINERAL ACIDS 

81. Strong mineral acids frequently act as catalysts in chemical 
reactions. 

Hydrochloric and sulphuric acids, employed in small amounts, 
bring about the rapid esterification of alcohols by organic acids (749). 
Hydrochloric acid shows itself also efficacious for the production of 
acetals from alcohols (782) as well as of similar compounds from 

*7 Lbmoins, Compt. rend., 162, 702 (1916). 

>• Sabatixb and Mailhs, Ann, Ckim. Phy$., (8), ao, 339 (1910). 

»• Sbndebins, BuU. Sac. Chim., (4), 3> 823 (1908). 

*« IPATIEF, BerichU, 3% 2986 (1904). 

^^ Sabatibb and Ebbil, Compt. rend., Z58, 668 (1914) and 259, 140 (1914). 

«* NoBMANN and Schick, Arch. Pharm., 253, 208 (1914), C. A., B, 3129. 



82 CATALYSIS IN ORGANIC CHEMISTRY 24 

glucose with alcohols and thiols.^' It also causes catalytic dehydra- 
tions in the condensation of ketones (795) and in analogous reactions. 

Sulphuric acid behaves similarly in the crotonization of aldehydes 
and in similar condensations. 

These two acids intervene in a similar manner in the acetylation 
of amines, e. g. of urea. Acetanhydride, without catalyst, gives a 
yield of only 19.3%, but 73.3% with one molecule of hydrochloric 
acid, and 61% with one molecule of sulphuric acid.^ 

82. But tiiese acids more frequently accomplish the reverse cat- 
alysis in causing hydrolysis, or decomposition by addition of water, 
and this aptitude they have in common with all strong soluble mineral 
acids, because it is in consequence of their ionization and should be 
considered as due to the hydrogen ions which they furnish. Their 
hydrolytic activity is proportional to their electrolytic dissociation. 

We have cases of this decomposition by the addition of water, 
in the various catalytic effects of acids in the saponification of enters 
and fats (314), the hydrolysis of amides (331), of anilides, of cer- 
tain aromatic sulphonic acids,^*^ of acetals, in the inversion of su- 
crose, and, in a more general manner, in the decomposition of 
polysaccharides such as starch and dextrine. 

Hydrochloric acid is a very active polymerizing catalyst for alde- 
hydes, whether it produces a simple aldolization with conservation 
of the aldehyde function (219), or a cyclization into molecules more 
or less condensed such as paraldehyde (222). 

Sulphuric acid, in small amounts, can likewise cause the change 
of acetaldehyde into paraldehyde and also the polymerization of 
ethylene hydrocarbons (210). 

Hydriodic add, in its capacity of a strong acid, can effect hy- 
drolyses, as do the above acids. We may mention also its use in facili- 
tating the preparation of the mixed organo-magnesium halides from 
chlorides in the Grignard reaction (302). 

NUtous acid catalyzes the transformation of oleic acid into its 
isomer, elaidic acid (186). 

INORGANIC BASES 

83. The alkalies, and alkaline earths, caustic potash and soda, 
baryta and lime, frequently act as catalysts. In inorganic chemistry 
they cause the rapid decomposition of hydrogen peroxide and hydro- 
gen persulphides. 

^ Emhi Fibchbb, Berichte, a6, 2400 (1893) and a;, 615 (1804). 
^ BoBSBKBN, Rec. Trav. Chim. Pays-Bas, ag, 330 (1910). 
«s Cbafts, Berichte, 34, 1350 (1901). 



25 ON CATALYSTS 87 

In water solution, these strong bases, being highly ionized, hy- 
drolyze esters rapidly. Saponification, when carried out in the pres- 
ence of excess of alkali, appears, at first sight, to be simply the conse- 
quence of the formation of the alkali salt of the acid of the ester, but, 
in reality, the phenomenon consists of two successive phases, first the 
hydrolysis which liberates the acid and then the neutralization of the 
acid to form the salt. 

Solutions of lime bring about rapid aldolization of aldehydes 
(221). 

A mixture of formaldehyde and acetaldehyde, on long contact 
with milk of lime, engenders a tetraprimary erythrol along with 
formic acid.** 

Solid caustic potash causes the aldolization of acetaldehyde and 
alcoholic potash, the pol3rmerization of isobutyric aldehyde (224). 

Caustic alkalies frequently produce isomerizations (185). 

FLUORIDES, CHLORIDES, BROMIDES, 

AND IODIDES 

84. Boron Fluoride. Among fluorides, that of boron merits 
special mention. It produces polymerizations of hydrocarbons: one 
part of it is sufficient to pol3rmerize 160 parts of oil of turpentine.*^ 

85. Iodine Chloride. The trichloride IC1„ the immediate 
product of the action of excess of chlorine on iodine, is a valuable 
agent in the direct chlorination of organic compoimds by gaseous 
chlorine (278). 

86. Barium Chloride. The anhydrous salt readily causes the 
decomposition of alkyl chlorides into hydrochloric acid and the ethy- 
lene hydrocarbons (876). 

87. Aluminum Chloride. The anhydrous chloride is a catalyst 
of immense value. It can be employed as an agent in direct chlorina- 
tion or bromination (284 and 293). 

It causes the direct fixation on benzene, of oxygen (263), of sul- 
phur (296) , and of sulphur dioxide (297) . 

It can bring about the decomposition of alkyl chlorides (877) and 
of thiophenol (297) . 

In the acetylation of urea it is a much more active catalyst than 
hydrochloric acid." 

Anhydrous aluminmn chloride is the basis of a very important 

" ToLLBNS and Wigand, Annalen, 365, 317 (1891). 
«7 Bbbthslot, Ann. Chim. Phya., (3), 38, 41 (1853). 
" BdmsiN, Bee. Trav. Chim. Payi-Bas, 29, 330 (1910). 



88 CATALYSIS IN ORGANIC CHEMISTRY 26 

general method for the condensation of organic compounds, which we 
owe to Friedel and Crafts/* and of which the principal applications 
and methods of operation will be set forth in Chapter XX. 

It acts powerfully on hydrocarbons to cause decompositions as 
well as molecular condensations (Chapter XXI). 

88. Ferric Chloride. Anhydrous ferric chloride can be substi- 
tuted for aluminum chloride in many of its catalytic reactions. It 
gives good results as agent of direct chlorination or bromination (285) 
and even of iodination (295). 

It can serve as catalyst in the production of acetals (781 and 783). 
It can replace alxmiinum chloride in the Friedel and Crafts 
synthesis (899) as well as in analogous condensations (902). 

89. Zinc Chloride. This chloride, having a strong affinity for 
water, is frequently employed as a dehydrating agent. The reactions 
which it produces are frequently considered as not catalytic, but a 
closer examination classes them as such, since they are generally pro- 
duced by small amounts of the salt, smaller than would be required 
for a chemical reaction. 

Thus zinc chloride is a well defined catalyst in the acetylation of 
glycerine by acetanhydride (761), in the crotonization of aldehydes 
(795), and in the formation of substituted indols by the decomposition 
of phenylhydrazones (633). Its rdle is less easy to define and to 
distinguish from that of an ordinary chemical reagent in quite a 
number of reactions, such ad the condensation of benzaldehyde with 
nitromethane,'® with chloral hydrate,'^ with ethyl orthoformate,** or 
with phthalic anhydride,*' or of phenols or polyphenols with aromatic 
amines,*^ or with fatty acids.** 

Anhydrous zinc chloride can replace aluminum chloride in the 
Friedel and Crafts synthesis (899) , and can also produce polymeriza- 
tions (211). 

Chlorides of Cobalt, Nickel, Cadmium, and Lead. These de- 
compose alkyl chlorides after the manner of barium chloride (876). 

90. Stannic Chloride. In certain condensations of organic 
molecules as of aliphatic aldehydes with phenols,** its rdle as a cat- 
alyst is difficult to define, as has been said of zinc chloride, or in the 

«• Fbiedbl and Cbafts, Ann. Chim. Phys, (6), x, 489 (1884). 

^ Priebb, Annalen, aas, 321 (1884). 

»^ BoBSSNBCK, BerichU, 19, 367 (1886). 

B< FiscRBB and K5bneb, Berichte, 17, 08 (1884). 

<^s Fischer, Annalen, ao6, 86 (1881). 

«« Calm, Berichte, z6, 2786 (1883). 

ss GoiAZWBia and Eaiseb, /. prakt. Chem., (2), 43> 01 (1891). 

»« Fabinyi, Berichte, ix, 283 (1878). 



27 ON CATALYSTS 97 

formation of phthalemes from phenols and phthalic anhydride,'^ but 
it is well established in the addition of acid chlorides to ethylene 
hydrocarbons (241). 

Chlorides of Antimony, Molybdenum, Thallium and Uranium. 
These can be used as chlorination catalysts (286). 

91. Cuprous Chloride, Bromide, and Iodide. These cause the 
decomposition of diazonium salts with the hydracids into the corre- 
sponding aromatic halogen compounds, with the elimination of nitro- 
gen (the Sandmeyer reaction) (606). They can bring about the 
decomposition of phenylhydrazine (611) as well as the production of 
indols by the decomposition of the phenylhydrazones (633) . Cuprous 
chloride causes the scission of chlorinated hydrocarbons (879). 
Cuprous iodide has been employed with success in the phenylation 
of primary aromatic amines (901). 

92. Mercuric Chloride. This accelerates the isomerization of 
isobutyl bromide (200) and permits acetaldehyde to be prepared by 
the hydration of acetylene (309). 

93. Aluminum Bromide. This is advantageously employed as 
catalyst in bromination. It causes rapid transformation of propyl 
bromide into the isomeric isopropyl bromide (199). 

94. Potassium Iodide. Organic chlorine derivatives usually re- 
act with less facility than the cbrresponding iodides. Their action 
can be greatly facilitated by the addition of 10% potassium iodide, 
which apparently permits the progressive transformation of the 
chloride into the more reactive iodide.^* 

95. Potassiimi Cyanide. It acts as an efficient catalyst of aldo- 
lization (220) and even of pol3rmerization in the strict sense (230). 

The double cyanide of potassium and copper has been employed 
as oxidation catalyst (268). 

INORGANIC SALTS OF OXYGEN ACIDS 

96. A large number of these salts can act as catalysts in organic 
reactions. 

Salts formed from weak acids or from weak bases or ammonia, 
readily separated by dissociation, usually show effects which could 
be produced by their constituents separately. 

97. Alkaline Carbonates. These may be used advantageously 
in place of caustic potash in reactions of aldolization or of analogous 
condensations (219 and 236). 

*7 Baetbb, Anruden, aoa, 154 (1880). 
•• Wok., BerichU, 39» 1051 (1906). 



98 CATALYSIS IN ORGANIC CHEMISTRY 28 

Potassium Bisulphate. This salt can act as free sulphuric acid, 
either in esterification or in the direct production of acetals, or in 
condensations effected with elimination of water such as that of 
dimethyl aniline with bensaldehyde.** 

Ammonium Sulphate, Nitrate, and Chloride. These can act as 
the free acids in esterification, or in analogous reactions, such as the 
production of acetals (783). 

98. Barium and Calcium Carbonates. These are equivalent to 
the free oxides. 

Calcium Sulphate. Either as the hydrate, or dehydrated below 
400°, it possesses a certain activity for dehydrating alcohols into the 
ethylene hydrocarbons (718). 

99. Aluminiun Sulphate and Phosphate. These are dehydra- 
tion catalysts analogous to free aliunina (718). 

Silicates. Clay and kaolin, hydrated silicates of aluminum, 
catalyze the dehydration of alcohols as does alimiina (717) . 

Broken glass, which is a mixed silicate of variable composition, 
has properties which vary with this composition. In the decomposi- 
tion of formic acid aroimd 300°, Jena glass yields mainly carbon di- 
oxide and hydrogen, while the ordinary white glass gives water and 
carbon monoxide, approaching piu^ silica (828). 

Pumice, in spite of its porous structure, is only slig^htly active as 
a catalyst and approaches silica in its action. 

100. Ferrous and Manganous Salts. In the presence of water, 
these are active oxidation catalysts (264). Thus the presence of 
various manganous salts aids the oxidation of oxalic acid solutions.^ 

101. Magnesium Sulphate. This is an excellent catalyst for the 
dehydration of glycerine into acrolein (725). 

102. Mercuric Sulphate. This can cause the hydration of 
acetylene hydrocarbons into ketones (309), and the oxidation of or- 
ganic compounds by fuming sulphuric acids (272). Its presence 
determines the natiu*e of the isomers produced in the direct sulphona- 
tion of aromatic molecules (816). It can also determine isomeriza- 
tions (195). 

103. Copper Sulphate. In Deacon'^ process, it is copper sulphate 
that catalyzes the oxidation of hydrochloric acid by air at 430° with 
the production of chlorine. It can, although with disadvantage, re- 
place mercuric sulphate in the oxidation of organic compounds by 
fuming sulphuric acid (272) . 

■> WiOXACH and W^btbn, BeriehU, z6, 149 (1883). 

^ JoBissBN and Rbcbbb, Zeit. physik. Chem., 31, 142 (1900). 



29 ON CATALYSTS 107 

VARIOUS COMPOUNDS 

104. Ammonia. The presence of ammonia favors the polymeriza- 
tion of cyanamide (233). 

Amines. Aliphatic primary and secondary amines are of use as 
catalysts in the complex reactions in the vulcanization of rubber. 
Piperidine has been suggested for the purpose."^ Nitrosodimethyl- 
aniline has been recommended in the ratio of 0.3 to 0.5 part to 100 
parts caoutchouc and 10 parts sulphur at 140®.** 

Alkyl Halides cand Esters. A small quantity of an alkyl iodide, 
especially methyl or ethyl iodide, greatly facilitates the preparation 
of the organo-magnesium compounds in the Grignard reaction, par- 
ticularly when chlorides are used (302). 

Acetaldehyde, heated to 100^ with ethyl iodide, condenses to par- 
aldehyde.*' 

Ethyl oxalate, by its presence, favors the reduction of ethylene 
bromide to ethyl bromide by the alloy of sodium and zinc.** 

Ethyl nitrite, in alcohol solution, causes the transformation of 
thiourea into ammonium isosulphocyanate. 

Ethers. Ethyl ether, as well as amyl ether, and anisol, 
C9H5.O.CH3, plays an important r61e as catalyst in the formation of 
the organo-magnesium complexes in the Grignard reaction (300). 

105. Aldehydes. Acetaldehyde provokes the hydration of cyan- 
ogen to oxamide (311). 

106. Organic Acids. Acetic add can sometimes act, after the 
fashion of mineral acids, to cause combinations with elimination of 
water, as in the production of acetals (780). Its catalytic r61e can 
be disputed in the condensation of benzaldehyde with malonic acid.*' 

Isoprene heated with acetic acid is transformed into artificial 
rubber (216). 

Oxalic add acts like hydrochloric or phosphoric acid in the poly- 
merization of aldehydes. 

107. Alkaline Acetates. Sodium acetate is a quite active dehy- 
dration catalyst. It produces the crotonization of aldehydes (795) 
as well as their simple polymerization. It is employed as a catalyst 
to aid in the esterification of alcohols by acetanhydride. 

Quite a large number of organic condensations, which take place 

•^ Batxb & Co., German Patent, 2e5|221 (1012), C. 1913, (2), 1444. 

«> PiAcmBT, English Patent, 4;263 of 1914. 

«* LjEBMS, Amuden, SuppL, z, 114 (1861). 

** Michael, Am. Chem. J,, 25, 419 (1901). 

*■ C!laisbn and Crismeb, Annalen, 21S, 155 (1883). 



108 CATALYSIS IN ORGANIC CHEMISTRY 30 

with elimination of water, have as their basis the use of sodium ace- 
tate, but it is usually employed in such large proportions that its 
catalytic rdle is masked. This is the case in the condensation of 
phthalid with phthalic anhydride to form diphthalid.** 

Likewise potassium acetate permits the condensation of acetic acid 
with phthalic anhydride to form phthalylacetic acid.*^ 

It is under the same conditions — that is, employed in large quan- 
tity — that sodiiun acetate causes acetanhydride to act on benzalde- 
hyde to form cinnamic acid in Perkin's synthesis.** 

108. Nitroso Compounds. The nitroso derivatives of methyU 
aniline, dimethylaniline, and diphenylamine are accelerators in the 
vulcanization of caoutchouc. The same property belongs to nitroso- 
phenol and nitrosonaphthol but not to the isomeric nitrosoamines.** 

109. Alkyl Cyanides. Methyl and ethyl cyanides are active cat- 
alysts in the reaction of sodium with alkyl iodides, or with similar 
compoimds (605). 

110. Fibrine. It may be recalled that fibrine catalytically de- 
composes hydrogen peroxide very rapidly. 

DURATION OF THE ACTION OF CATALYSTS 

111. It would seem, by definition, that the action of catalysts 
should be prolonged indefinitely, and this perpetuity would be assured 
to them if they did not suffer any alteration in the course of the re- 
actions which they effect. If any change does take place, as is most 
frequently the case with solid catalysts acting in gaseous or liquid 
media, an alteration of the surface, even slight, brings on progressive 
diminution of activity which may go as far as total suppression. 

In hydrogenations carried on by nickel in gaseous systems, using 
pure and sufficiently volatile substances and thoroughly purified hy- 
drogen, at a carefully regulated temperature, the action can be con- 
tinued by the same metal a very long time without appreciable 
weakening. Sabatier and Senderens were able to effect the trans- 
formation of benzene into cyclohexane for more than a month with 
the same nickel, the operation being interrupted every evening and 
.resumed in the morning. The slight oxidation which the metal suf- 
fered over night, in the cold tube, caused no inconvenience because 
the oxide was again reduced by the hydrogen at the beginning of the 
next TunJ^ 

** Gbaebb and Gutb, Annalen, 233, 241 (1886). 

*^ Gabriel and Neumann, Berichte, 26, 025 (1893). 

«« Perkin, /. Chem. Soc, 31, 388 (1877). 

•» Peachet, /. 80c. Chem. Ind., 36, 424 (1917). 

^^ Sabatieb and Sbndbbbns, Ann. Chim. Phy$., (8), 4> 334 (1906). 



31 ON CATALYSTS 114 

112. Poisoning of Catalysts. On the contrary, traces of chlorine, 
bromine, iodine and sulphur in the system are frequently sufficient 
to suppress the activity of the nickel entirely. It appears to be 
poisoned. Benzene which is not absolutely free from thiophene can 
not be hydrogenated. An infinitely small amount of bromine in 
phenol renders it incapable of being changed into cyclohexanol.^^ 
Chlorine or bromine derivatives of benzene have never been hydro- 
genated since the first portions of these compounds alter the metal 
immediately in an irremediable manner. 

113. But the conditions under which this poisoning of the metal 
take place are quite complex. The presence of free halogens or halo- 
gen acids in the hydrogen is much less harmful than the presence of 
combined halogen in the vapors submitted to hydrogenation. This 
has been observed by Sabatier and Espil in the hydrogenation of 
benzene.^* 

In an apparatus in which the hydrogenation of benzene was pro- 
gressing regularly over nickel at 180^, the benzene was replaced by 
benzene containing 0.5% iodine. The hydrogenation continued for 
several hours with an excellent yield. The escaping hydrogen, after 
the condensation of the cyclohexane, disengaged abimdant fmnes of 
hydriodic acid showing that the iodine had been hydrogenated by the 
catalyst. The operation was interrupted after 130 g. of cyclohexane 
had been collected and it was found that the nickel had combined 
with iodine in the first half only of the tube. This half was incapable 
of carrying on the hydrogenation but the other half was unhurt. The 
poisoning of the metal by the iodine had taken place only slowly and 
step by step; the hydriodic acid had had, on its own account, no 
harmful effect and had not converted into the iodide the metal the 
surface of which was covered with an unstable hydride which pro- 
duced the hydrogenation (167). Doubtless the fixation of the hydro- 
gen on the iodine and the benzene in contact with the nickel is much 
more rapid than the reaction of the nickel with the iodine or with the 
hydriodic acid. As in the direct hydrogenation of unsaturated hydro- 
carbons (422) , the metal protects itself, by its own action, against the 
permanent alteration which would render it inactive. 

114. Similar results have been obtained, by the same authors, in 
hydrogenating benzene with hydrogen containing hydrogen chloride, 
but if traces of brombenzene or chlorbenzene are added to the ben- 
zene, the production of cyclohexane ceases almost immediately and 
the nickel is incapable of regaining its activity. 

^^ Sabaties and Mah^he, Compt, rend., 153, 160 (1911). 
" Sabatikb and Esph., Bull. Soc. Chim., (4), 15, 778 (1914). 



116 CATALYSIS IN ORGANIC CHEMISTRY 32 

It is plain that free chlorine or bromine in the hydrogen, unlike 
iodine, would produce a definite poisoning of the metal since they 
would offer the possibility of direct substitution in the benzene which 
iodine does not do. 

Sabatier and Espil have likewise been able, for several hours, to 
transform into cyclohexane benzene containing 10% of carbon disul- 
phide, but traces of thiophene added to the benzene stopped the re- 
action at once. 

115. The use in the oil industry (937 et seq.) of nickel as hydro- 
genation catalyst suspended in the liquid, has led to the determina- 
tion of the greater or less toxicity of a number of substances which 
may be present in small amoimts in the oils to be treated. 

The soaps formed from the various metals or oxides are, from this 
point of view, very dissimilar: while those of nickel, thorium, ceriimi, 
aliuninum, and calcium are absolutely without harmful effect, those 
of potassium, barium, zinc, cadmium, lead, and uranium are harmful. 

The nickel salts of organic monobasic acids, as well as of lactic, 
oxalic, and succinic acids, are without effect. The same can be said 
of the free fatty acids such as acetic and stearic, but oxystearic, malic, 
tartaric and citric acids are true poisons for the nickel catalyst. 
Toxicity is also shown by calcium hydroxide, potash, boric acid, am- 
monium molybdate, as well as by sulphur, selenium, red phosphorus, 
glycerine, lecithine, morphine, strychnine, amygdaline, and cyanides. 
Tin and aluminum in powder are without action, but iron, lead, and 
zinc are harmful.^' 

116. With a platiniun catalyst, the extreme toxicity of compounds 
of sulphur,^^ phosphorus and arsenic and of cyanides, etc., has long 
been known. The activity of colloidal platinum is diminished or 
destroyed by a large number of materials. Their toxicity has been 
measured by means of the velocities of decomposition of hydrogen 
peroxide and it has been suggested to designate by the term toxicity, 
the dilution (in liters per gram-molecule) at which the velocity of 
decomposition in contact with 0.000,01 gram-atom of platinimi, is 
reduced one-half.^' 

Among the violent poisons, hydrocyaruc acid stands at the head 
with toxicity 21,000,000, followed by iodine with 7,000,000, mercuric 
chloride with 2,500,000, sodium hyposulphite, carbon disulphide, car- 
bon monoxide, and phosphorus. Among the moderate poisons, are 
placed aniline with toxicity, 30,000, bromine with 23,000, hydrochloric 

^* Sbcchidbno, /. Chem. Ind., Tokyo, ax, 898 (1918). 

T* TuBNBB, Pogg. Ann., a, 210 (1824). 

V* Bredig and Iksda, Zeit. phya. Chem., 37, 1 (1901). 



33 ON CATALYSTS 119 

add with 3,100, oxalic acid, amyl nitrite, arsenious acid, and ammo- 
nium chloride. Among the feeble poisons, are foimd pho^horus 
acid, 900, sodium nitrite, and hydrofluoric acid, while potassium 
chlorate, alcohol, ether and pinene have no toxicity and formic acid, 
hydrazine, and dilute nitric acid are rather favorable. These toxicity 
coefficients would certainly be very different if measured with 
platinum black or sponge.''^ 

117. Platinum black is very sensitive to the poisons enumerated 
for colloidal platinum. Traces of potassium cyanide are sufficient to 
take from the metal all power to hydrogenate the aromatic nucleus, 
and also to weaken greatly the hydrogenation of ethylene bonds.^^ 

Contrary to what has been said about colloidal platinum, the 
hydrogenation velocity of pinene is diminished if it is dissolved in 
alcohol or in any substance capable of furnishing alcohol e. g. ether 
or ethyl acetate. The fatty acids have little action, except formic, 
which has a marked toxic effect.^® 

118. The Fouling of Catalysts. Other causes of alteration can 
come in to bring on the decline of catalysts. It happens quite fre- 
quently that, along with the principal reaction, there are side reactions 
which become more important at elevated temperatures and which 
give rise to highly condensed substances which are only slightly 
volatile, carbonaceous or tarry. • Such substances are slowly deposited 
on the active surfaces where they hinder the contact with the gas, 
rendering the useful reaction slow. 

In hydrogenations, or decompositions by finely divided metals, the 
more active the metals, the more rapid are formations of this sort 
The most fiery catalysts are the most rapidly enfeebled. 

The decline of a catalyst, either from poisoning or fouling, is indi- 
cated by the diminishing of the yields in the reaction which it 
catalyzes. 

When a fatigued nickel catalyst is dissolved in dilute hydrochloric 
acid, fetid hydrocarbons are evolved with the hydrogen and brown 
carbonaceous or viscous materials are deposited. 

119. It can be seen that an analogous enfeeblement will take place 
when the reaction produces a material which is only slightly volatile 
at the temperature of the tube and which impregnates the metal more 
or less rapidly thus opposing its regular activity. . This takes place 
in the hydrogenation of aniline in the presence of nickel at 190^, since 

^* See compreheiisiye article by Bancboft J. Phys. Chem,, az, 767 (1917). 
^^ Madinavhtia, Soc. Espan, Phys. Chim,, zz, 328 (1913). 
^^ B5BBEXXN, VAN DER WiiDB and MoM, Rev^ Trav, Chim. Paya-Bas, 35, 
260 (1916). 



120 CATALYSIS IN ORGANIC CHEMISTRY 34 

there is produced, in addition to the cyclohexyl amine boiling at 134^, 
two other amines which are only slightly volatile, dicyclohexyl amine 
and cyclohexyl aniline, which boiling above 250°, are carried off with 
difficulty by the hydrogen and remain partly in the liquid form in 
contact with the metal. 

120. It is to avoid analogous effects that it is necessary to watch 
that the metal is never wetted by an excessive flow of the liquid which 
is being used or in consequence of an accidental lowering of the tem- 
perature of the tube. In the preparation of cyclohexanol or its 
homologs by the hydrogenation of phenol or the cresols, the reaction 
is carried on at a temperature only a little above the boiling points 
of the liquids and it happens sometimes that the nickel is wetted by 
the liquid. The catalyst immediately becomes nearly inactive, be- 
cause the surface is, without doubt, altered permanently by contact 
with the liquid phenol or cresol. 

121. Catalytic hydrogenation by finely divided metals is, to a 
certain extent, comparable to the action of the figured ferments/* 
As with these, there are three periods, an initial period in which the 
catalyst adapts itself to its function, a period of normal activity and 
a period of decline, ending in the death of the ferment. 

The first period is a variable state and is usually of short dura- 
tion: it corresponds, without doubt, to the superficial modification 
which the metal undergoes when the atmosphere of pure hydrogen 
which surroimded it, is replaced by a mixture of the vapors with 
hydrogen. 

The second period, that of normal fimctioning, is usually very long 
and would be indefinite unless something is passed in or is produced 
which can alter the surface of the metal. Such substances may enter 
with the hydrogen or with the substance to be hydrogenated or may 
be produced in the reaction. 

122. Catal3rtic oxides, although less sensitive than the metals to 
chemical alterations of their surfaces, may, nevertheless, suffer from 
this cause notable diminution of activity even to complete suppres- 
sion of their fimction. In many cases they are so fouled that they 
are weakened or paralyzed. 

123. Regeneration of altered Catalysts. In so far as the alter- 
ation of metallic catalysts is due simply to fouling by deposits of 
carbon or of tarry substances, calcination in a current of air is suf- 

T» " Figured ferments " is an obsolete expression for " organized ferments/* 
meaning ferments in which cells can be found with the microscope, as in the 
yeasts; in contradistinction to such ferments as saliva, etc. The cells were 
spoken of as " figures," hence '' figured ferments." — H. S. Jenninos. 



35 ON CATALYSTS 126 

ficient to bum off these substances, converting the metal (nickel, iron, 
copper) into the oxide which a new reduction, carried out at a suitable 
temperature, will reconvert to the metal. These operations can be 
carried out in turn in the tube itself in which the catalysis takes 
place. 

This procedure is not suitable for platmum black, which by being 
heated to redness loses nearly all of its catal3rtic activity (63). 

It does not serve well for the greater part of the metal oxides which 
are greatly diminished in activity by heating to a high temperature; 
but it does serve well for thoria which has been fouled by long use 
(708). 

124. Metallic catalysts poisoned by vapors of chlorine, bromine, 
iodine, sulphur, etc., are difficult to revivify except by dissolving in 
a suitable acid and working over completely. 

Calcination does not remove chlorine from slightly chlorinated 
nickel. The action of hydrogen reduces the chloride to the metallic 
state below 400^, but the resisting metal is in a peculiar fibrous state 
and is incapable of reducing benzene to cyclohexane. Even after 
oxidation and a second reduction it is a poor catalyst. 

125. It can be slowly restored to complete activity by employing 
it for some time in the reduction of nitrobenzene to aniline, work 
which poisoned nickel is still capable of doing. The aniline which is 
produced contains increasing amoimts of cyclohexyl amine. After 
some hours of this treatment the power of the metal to produce cyclo- 
hexane from benzene is completely restored. On the contrary, poison- 
ing by bromine or iodine seems to resist this treatment.*^ 

MIXTURE OF CATALYSTS WITH INERT 

MATERIALS 

126. The desire to increase the active surface of solid catalysts 
had led to disseminating them over inert porous materials such as 
pumice, asbestos, infusorial earth, and various metal salts. This 
practice has appeared specially advantageous for expensive catalysts 
such as platinmn and palladium. Thus in the manufacture of sul- 
phuric acid by the contact process, the catalytic masses are either 
platinued asbestos, or anhydrous magnesium sulphate impregnated 
with platinum (about 14 g. metal per kilogram of sulphate) . 

Nickeled pumice which has been employed by certain chemists in 
place of nickel powder for hydrogenations, is readily prepared by 
incorporating the crushed pumice in a thick paste of precipitated 

^ BAMArmi and EsnL, BvU. 8oc, Chim., (4), 15, 779 (1914). 



127 CATALYSIS IN ORGANIC CHEMISTRY 36 

nickel hydroxide, drying in the oven, and finally reducing in the tube 
that is to be used for the hydrogenations.'^ 

127. In the case of catal3rtic metals which have to be carried to a 
red heat (932), the use of inert siliceous carriers may have serious 
consequences owing to the formation of silicates which may suppress 
the activity of the metal. In such cases it is best to use carriers free 
from silica, such as magnesia, alumina, natural bauxite, lime or car- 
bonate of calcium, etc., either by employing these substances in 
powders intimately mixed with the oxides, the reduction of which is 
to furnish the metals, or by previously sticking together these mixtures 
in little lumps with the aid of non-siliceous materials (Sabatier and 
Mailhe) . 

128. In certain cases the use of inert supports for solid catalysts 
can lead to serious trouble. When the catalyst is to be heated on a 
furnace, it is disposed in a thin layer in the tube. By a fear entirely 
xmjustified, in view of the great velocity of diffusion of hot gases, 
some have doubted the sufficiency of the contact between the gas, 
circulating too freely in the upper part of the tube, and the catalyst. 
Guided by this thought, the whole height of the tube has been filled 
with the pumice impregnated with the catalyst. But these conditions 
are not favorable, since the temperature varies much from bottom to 
top of the tube. On the contrary, filling the tube entirely with the 
catalytic mass presents no inconvenience when the tube is heated all 
around as, for example, by an electric resistance wound around it. 

•1 Bbunkl, Ann. Chim. Phys,, (8), 6, 205 (1906). 



CHAPTER III 
THE MECHANISM OF CATALYSIS 

129. The extreme diversity of catal3rtic reactions makes it evident 
that difficulties will be encountered in giving an explanation that will 
fit all cases. 

Berzelius, who was the first to define catalytic phenomena and 
to ^ve them this name (4) did not really furnish any explanation 
for them and foimd only vague terms with which to characterize the 
catalytic force which he regarded as the cause of reactions of this 
kind. '^ It is evident/' said he, '' that the catal3rtic force acts princi- 
pally by means of the polarity of the atoms which it augments, 
diminishes or changes. In other words, the catalytic force manifests 
itself by the excitation of electrical relations which, up to the present, 
have escaped our investigation."^ And he adds: ''From all that 
precedes, it follows necessarily that the sources of power (light, heat, 
electricity) contain the cause of the activity of matter, which, without 
their influence, would be inert and in a state of unalterable and eternal 
repose." 

To the mind of Berzelius, catalytic forces are then of the order of 
the sources of power " different effects of one first cause which, imder 
definite circumstances, pass from one modification into another."* 
But their nature remains no less mysterious: the calorific phenomena, 
sometimes intense, which frequently accompany catalyses, may be 
the consequences rather than the determining cause. 

130. In a great number of catalyses, such as are realized by plati- 
num black and by finely divided metals prepared by reduction of 
oxides, the porous state seems, at least at first sight, to be the deter- 
mining cause of the catalytic activity and this thought is the basis of 
the explanation that has been given of the mechanism of catalysis 
and which, accepted readily by many chemists, has been usually 
elaborated in treatises. 

I BsBZBLiuB, TndU de Chemie, 2nd Ed., Paris, 1845, I, 112. 
s Bebzeuub, loc. ciL, 96. 



87 



181 CATALYSIS IN ORGANIC CHEMISTRY 38 

PHYSICAL THEORY OP CATALYSIS 

131. Porous materials, whose surfaces are very large as compared 
with their masses, enjoy the property of absorbing gases with more 
or less energy. A case of the absorption of gases by solids, that has 
been much studied, is that of wood charcoal. 

When 1.57 g. coconut charcoal, corresponding to 1 cc. of compact 
carbon, has been heated to redness and cooled under mercury, it ab- 
sorbs m the cold (at 15^ and 760 mm.) quite various volumes of gases, 
all the way from 2 cc. for argon to 178 cc. for ammonia. These 
volumes increase nearly proportionally with pressure and decrease 
greatly when the temperature is raised. 

The volume mentioned above for ammonia shows that this gas, 
if compressed to a volume equal to the total voliune of the charcoal 
would require a pressure of 178 atmospheres, and as this gas is lique- 
fied at 15^ imder 5.5 atmospheres, it is necessary to assume that the 
ammonia exists in the pores of the charcoal in the liquid condition, 
in which it would occupy a volume of about 0.2 cc. (from the known 
density of liquid ammonia). 

The absorption of the gas by the carbon liberates much heat and 
this amount of heat is even larger than that obtained by the lique- 
faction of the gas. Thus the amoimts of heat per cubic centimeter 
of gas are: * 

Absorption by 

carbon lAquejaction 

Sulphur dioxide 0.61 to 0.47 cal. 0.26 cal. 

Ammonia 0.45 to 0.33 cal. 0.20 cal. 

For ammonia, the heat of absorption is little different from the 
heat of solution in water and is much larger than the heat of solution 
in the case of sulphur dioxide.^ 

For hydrogen, the heat of absorption by carbon is six times the 
heat of liquefaction (Dewar). 

132. To explain these singular phenomena, it is assumed that the 
enormous attraction of the surface of the cavities of the wood char- 
coal causes the accumulation of the gases in the cavities, at pressures 
which are not very great for the permanent gases (argon, hydrogen, 
nitrogen) , however, exceeding 35 atmospheres for oxygen, but which 
are very high for the easily liquefiable gases, generally much greater 

* Favbi and SnjmiMANN, Ann. Chim, Phys^ (3), 37^ 465 (1853). Riqnattlt, 
Ibid., (4), 34. 247 (1871). 

* Lb Chatiubb, LegonB mar le Carbone, Paris, 1908, p. 133. 



39 THE MECHANISM OF CATALYSIS 136 

than the pressures required for liquefaction: this liquefaction would 
be actually accompanied by a strong compression of the thin layer 
of liquid produced on the carbon walls. This compression would be 
responsible for the excess of the heat of absorption over that of 
liquefaction. 

133. An analogous evolution of heat has been observed when any 
liquid whatever is absorbed by a solid having a very large surface, 
such as a fine powder, and is called heat of imbibition. 

Powdered quartZy with grains averaging 0.005 mm. diameter, 
disengages per gram, when wetted: 

With water 14 calories 

With benzene 4 " 

Calculating the surface of the grains, the heat of wetting by water 
appears to be 0.00105 cal. for 1 sq. cm. of quartz at 7^. 

It has been shown likewise, that the wetting by water of 1 g. 
starch evolves 22 calories, 1 g. wood charcoal, 7 calories, 1 g. alumina, 
2 calories. 

134. The absorption of gases in the pores of the carbon is equiva- 
lent to compressing the gases to a greater or less pressure. Simul- 
taneously there is the liberation of considerable heat by the absorp- 
tion. It is imagined that the heat and pressure cause reactions to 
take place. Hydrogen and chlorine may \mite in the cold when they 
meet each other thus in the pores of the carbon, and it is the same 
way with carbon monoxide and chlorine and with hydrogen sulphide 
and oxygen. 

The oxygen which is absorbed combines little by little with the 
carbon in the cold to give carbon dioxide. When the gases are 
pumped out of wood charcoal, which has been exposed to air, scarcely 
anything is obtained except nitrogen and carbon dioxide. 

It would seem then that porous carbon should be a universal cat- 
alyst for all gas reactions, lowering the reaction temperatures greatly. 
However, except for the formation of carbonyl chloride (282) , carbon 
is a mediocre catalyst and of little use, doubtless because gaseous 
interchanges do not take place rapidly enough in it. 

135. Various powdered substances have greater or less power of 
absorbing gases, but generally, especially for oxides and salts, this 
power is not great. 

Finely divided metals are, in certain cases, able to absorb consid- 
erable amoimts of gases, but this aptitude is always specific and 
limited to a small number of gases. In the case of charcoal, the 
amounts of various gases absorbed are roughly in proportion to their 



136 CATALYSIS IN ORGANIC CHEMISTRY 40 

ease of liquefaction, while with metals the absorption is markedly 
characterized by a sort of selective affinity. 

136. It is one of the most difficultly liquefiable gases, hydrogen, 
that is absorbed the most readily by metallic powders. The maximum 
of such absorption is shown by pdlladium, which, in the form of 
sponge, can absorb 680 to 850 times its own volume of hydrogen, 
whatever be the pressure of the gas, provided the pressure be not too 
low: for all of the hydrogen is given up in a vacuum, even in the 
cold." 

At 20°, platinum black absorbs 110 volumes of hydrogen, what- 
ever the pressure, provided it is more than 200 mm., and here, like- 
wise, the hydrogen is given up in a vacuimi.* 

Reduced cobalt can absorb 153 volumes of hydrogen, finely divided 
gold, 46, reduced iron or reduced nickel, up to 19, and reduced copper, 
only 4.^ 

137. The precious metals have an analogous, though less energetic 
affinity for oxygen. Thus p^tinum black absorbs up to 100 volumes 
of oxygen in the cold and here again this amount is not increased by 
additional pressure and all of the gas is given up in a vacuum. 

Finely divided gold and silver can also take up greater or less 
amoimts of oxygen.® 

138. The activity of these finely divided metals, as hydrogenation 
or oxidation catalysts, would then be due to their power to absorb 
hydrogen or oxygen along with the vapor which is to be transformed. 
The compression and local heating thus produced would cause the 
reaction to take place which without this help would have required 
a much higher temperature, frequently a temperature so high that 
the products would not be stable. 

The dehydrations of alcohols which are effected by contact with 
alumina, would result from the condensation of the alcohol vapors in 
the pores of the alumina, this condensation producing effects compa- 
rable to superheating the vapors. 

139. The powdered or porous state would be a sufficient condition 
to produce such effects, since a body containing an infinite number 
of very small cavities, offers the possibility of realizing simultaneously 

" MoND, Ramsay, and Shieids, Phil, Tram, Roy, Soc, z86, 657 (1896). 
Proc. Boy, Soc, 62, 50 and 290 (1807). Dewab, Chem. News, 76, 274 (1897). 

^ MoND, Ramsat and Shisids, Phil, Trans. Roy, Soc, z86» 675 (1896). 

^ Moibban, Traits de Chimie Mineral, I, 13. 

® Neumann, Monaish^ Z3> ^ (1892). Mond, Rambat and Shibij>s, Proc. 
Roy. Soc, 6a, 50 (1897) and Zeit, phys. Chem., 35, 657 (1808). Rambat and 
Shields, PhU, Trans, Roy. Soc, z86, 657 (1896). Englbr and Wochubb, Zeit. 
anorg. Chem., ag, 1 (1901). 



41 THE MECHANISM OF CATALYSIS 112 

all possible temperatures and all possible pressures thus causing a 
jgreat number of reactions by condensation and heating.* To this 
local pressure, there is added also, in the case of metals, the effect of 
immediate contact with a good conductor and, consequently, electrical 
influences which might aid.^^ 

140. A reaction which, without the aid of the catalyst, would take 
place at an infinitely slow rate, at the temperature of the experiment, 
would thus receive, on account of the pressure of the catalyst, an 
immense acceleration and go to completion in a relatively short time. 

Catalysis would then be, as Ostwald^^ has defined it, only the 
acceleration of a chemical phenomenon which otherwise would take 
place slowly. The presence of the catalyst in the system suppresses 
the chemical friction which slows up the reaction to the point of stop- 
ping it entirely. Its r61e would then, be similar to that of oil in clock- 
work, the movement of which it accelerates, though the forces which 
produce the movement are not increased. 

141. This physical explanation, applicable to all porous catalysts, 
meets with objections numerous and difficult to get rid of. 

Right at the start, the cause which determines the condensation 
of gases and vapors in the pores of a solid remains mysterious and 
inexplicable; this physical attraction of solids for gaseous substances 
presents no visible relation to the properties of the gases. The absorp- 
tion by wood charcoal is indeed greater for gases which are readily 
liquefied, but it is just the other way with platinum and various metal 
powders where the gas that is most absorbed is hydrogen which is 
very difficult to liquefy. 

The same theory is difficult to apply to the case where hydrogen 
is taken up with the aid of platinum black or nickel held in suspen- 
sion in a liquid medium (Chapters XI and XII) , and even more dif- 
ficult where the catalyst is colloidal platinum or palladium: for it is 
difficult to see how high local pressiures and temperatures could be 
developed in such cases. 

142. Furthermore, a purely physical conception of the causes of 
the reaction does not take account of the specificity of cabalysU and 
of the remarkable diversity of the effects produced. 

At the same temperature, 300^, the vapors of an alcohol, isobutyl, 
for example, decompose: 

in the presence of copper, into aldehyde and hydrogen, exclusively ; 
in the presence of alumina, into isobutylene and water, exclusively ; 

• DucLAUX, Compt. rend., xsa, 1176 (1911). 
i<> van't Honr, Legont de Chim. Phys., 1898, 3, 216. 
^ OsTWALD, Rev. 8ci., zgoa (1)» 640. 



143 CATALYSIS IN ORGANIC CHEMISTRY 42 

in the presence of vxamum oxide, both ways, giving at the same 
time the aldehyde and isobutylene. 

Manganoui oxide gives the same decomposition as copper, only 
slowly. 

If we assmne that the metallic characteristic of conductivity 
accoimts for the fundamental difference between copper and alumina; 
we can not explain the differences between alumina, and the oxides 
of manganese and uranium, if the physical condensation in the pores 
of the catalyst is the sole cause of catalysis. 

The action of the catalytic oxide can not be entirely like an eleva- 
tion of temperature, since the direction of the reaction is intimately 
connected, not with the physical state of the oxide, but with its 
chemical nature. 

143. The decomposition of formic acid furnishes a no less striking 
example of the specificity of catalysts (821). Finely divided metals 
and likewise zinc oxide, decompose this acid into hydrogen and carbon 
dioxide exclusively, but at tKe same temperature, titanium oxide gives 
carbon monoxide and water exclusively, while certain oxides, as 
thoria, bring about a mixed reaction, more or less complicated by the 
production of formaldehyde and even of methyl alcohol. 

Yet from the physical point of view there does not appear to be 
any great difference between the oxides of zinc, titanium, and thoriiun. 

144. Furthermore, this explanation of catalysis can not possibly 
apply to the effects of liquid catalysts in homogeneous systems and 
it is hard to imagine that there are fundamental differences between 
the various kinds of catalysis. 



CHEMICAL THEORY OF CATALYSIS 

145. An entirely general explanation of catalytic phenomena can 
be based on the idea of the temporary formation of imstable chemical 
compounds which, serving as intermediate steps in the reaction, 
determine its direction or increase its velocity. 

In order to arrive at a clearer idea of the catalytic mechan- 
ism, a special case can be first considered which can be classed 
as catalytic and which can be designated by the name reciprocal 

catalysis. 

146. Reciprocal Catalysis. Suppose two distinct chemical 
systems capable of reacting independently, each on its own account: 
however, each one of them, if left to itself, remains in false equilibrium 
or, at least, reacts with extreme slowness. But if these two systems 



43 THE MECHANISM OP CATALYSIS 148 

are mixed, they mutually catalyze each other and the two reactions 
proceed simultaneously very rapidly in correlative proportions.^* 

147. An example is furnished by hydrogen peroxide, opposed by 
chromic acid, H^CrO^. The hydrogen peroxide tends to decompose 
into water and oxygen, but in the cold, this spontaneous decomposi- 
tion is very slow and would require more than a year. 

The chromic acid solution, acidified with sulphuric acid, is also 
stable in the cold, but, if heated it decomposes with evolution of 
oxygen. On heating, we would have: 

3 HA — SHaO + 30 
and 2 H^CrO^ + 3 H^SO^ — Or, (SO J « + 5 H,0 + 3 0. 

But if the two solutions are mixed cold, in the exact proportions 
represented by the formulae above, there is inunediate decomposition, 
simultaneous and complete, of both the hydrogen peroxide and the 
chromic acid, and this decomposition, manifested by a brisk effer- 
vescence of oxygen, takes place in such a manner that the amount of 
oxygen coming from the hydrogen peroxide is exactly the same as 
that from the chromic acid. 

This proportionality indicates the cause of the reaction, which is 
apparently the production of an imstable combination of hydrogen 
peroxide and chromic acid in the proportion 3 H2O2 : 2 H2Cr04. 
As soon as this compound is formed, it decomposes, with liberation 
of oxygen, leaving water and chromic oxide which dissolves in the 
sulphuric acid present. 

This fugitive combination, the temporary formation of which de- 
stroys the false equilibrum of the two systems, really exists: for it 
appears as an intense blue coloration, when the two liquids are mixed, 
and can even be isolated. If a dilute solution of hydrogen peroxide 
is poured into a slight excess of chromic acid: in place of a stormy 
effervescence a blue solution is obtained. When this is shaken with 
ether, the dark blue imstable compoimd passes into the ether. The 
evaporation of the ether at — ^20*^, leaves a dark blue oil, which, on 
warming to room temperature, decomposes into chromic oxide, water, 
and oxygen. We have in succession,^' 

2H2Cr04 + 3 HA — 4 H^O + H^Cr^Oio 

H^Cr^Oio - Cr A + H^O + 3 O^. 

148. Another example of reciprocal catalysis is offered by an acid 
solution of potassium permanganate opposed by hydrogen peroxide. 

1* SABATDBy Rev. gSn, de Chimie pure et app., 17, 185 (1914). 
1* MoiBSAN, TraiU de Chimie Min^ I, 275 (1901). 



149 CATALYSIS IN ORGANIC CHEMISTRY 44 

The permanganate which is itself an energetic oxidising agent, reduces 
the hydrogen peroxide immediately, and is itself reduced. Here again 
there is exact equality between the amounts of oxygen coming from 
the two reacting substances. 

A solution of potassium permanganate, acidified with sulphuric 
acid, is stable in the cold, but when heated there is a slow reaction: 

2 KMnO^ + S HgSO^ — 2 MnSO^ + K^G^ + S H,0 + 5 0. 

Likewise the hydrogen peroxide alone would give very slowly in the 
cold: 

6 HA-6 H,0 + 6 0. 

On mixing the two solutions there is immediately a vigorous effer- 
vescence, liberating 10 0. The reaction ia quantitative and is used 
practically for the estimation of hydrogen peroxide by titrating with 
standard potassium pennanganate solution. As in the case of 
chromic acid, this proportionality indicates the formation of an un- 
stable compoimd, the decomposition of which disengages 5 O2 ; but in 
this case it is difficult to detect. According to Berthelot, the perman- 
ganate acts on hydrogen peroxide to substitute hydroxy! groups for 
the hydrogen atoms, furnishing a sort of hydrogen tetroxide: 

a--OH 
0— OH 

which is very unstable and soon decomposes into water and 3 0. 
When the solutions are mixed at —12^, the permanganate is de- 
colorised without the evolution of oxygen, but the colorless tetroxide, 
stable at — 12^, decomposes on warming, liberating the oxygen. Po- 
tassium and caesium tetroxide, which are known, are the alkaline 
salts of this hydrogen tetroxide.^^ 

Thus in reciprocal catalysis the simultaneous and correlated re- 
actions of two systems, which apart only tend to react, are determined 
by the production of an imstable combination which serves as a 
common intermediate product for the two reactions. This inter- 
mediate compound is sometimes visible as in the case of the hydrogen 
peroxide-chromic acid and sometimes difficult to perceive as in the 
case of the hydrogen peroxide-permanganate mixture. 

149. Induced Catalysis. Suppose a chemical system which tends 
to react but which remains in false equilibrum or imdergoes change 
infinitely slowly. But if another system which is reacting rapidly 
in an analogous manner be associated with the first, the first system 
is drawn into the reaction, without the second seeming to take any 

^* Bbrtrblot, Am, Chim. Phys. (5), az, 176 (1880) and (7), aa, 433 (1901). 



45 THE MECHANISM OF CATALYSIS 151 

part in the reaction of the firsti except, so to speak, setting it an ex- 
ample. This may be called induced catcdysia, and, as in the case of 
reciprocal catalysis, there is foimd to be a proportionality between 
the two reactions. 

Frequent examples of reactions of this sort are found among oxida- 
tions by oxygen gas and are called auto-oxidations. 

150. Auto-oxidations. A large number of substances directly 
Qxidisable by oxygen, or by air, stimulate by their own oxidation 
that of substances which, without this circumstance, would not be 
directly oxidisable. 

Thus palladium hydride when allowed to oxidise spontaneously 
in water solution, causes intense oxidations; indigo is decolorized and 
potassium iodide is oxidised into potassium hydroxide and iodine; 
ammonia goes into nitric acid, benzene into phenol, and toluene into 
benzoic acid. Carbon monoxide is oxidised to the dioxide, an oxida- 
tion which ozone and hydrogen peroxide are incapable of 
accomplishing.^" 

Ethyl alcohol, exposed to the simultaneous action of sunlight and 
air, is not appreciably changed, but in the presence of xylene, which 
is oxidised, the alcohol goes into acetic acid: under the same condi- 
tions, amyl alcohol gives valeric acid, and mannite yields mannose.^* 

Oxidations of the same nature accompany the spontaneous oxida- 
tion of phosphorus in moist air, of turpentine, of aqueous solutions of 
pyrogallol, of alkaline sulphites, of ferrous hydroxide, of ammoniacal 
cuprous salts, of benzaldehyde, etc. Such substances are called auto- 
oxidisers, and experiment has shown that in every case they render 
active, that is to say, able to oxidise substances otherwise not 
attacked, exactly the same amoimt of oxygen as they use up in their 
own oxidation.^^ 

151. The cause of the phenomenon appears to be that the auto- 
oxidiser takes up oxygen to form a sort of peroxide Which is then 
destroyed in the oxidation of the associated substance. 

The auto-oxidiser, A, alone would give: 

A + 0— O — AC - 

» Hoppi-l^iTLEB, BerichU, za, 1551 (1879) ; z6, 1917 (1883) ; ao, R795 
(1887); Baumann, Ibid., z6, 2146 (1883); 17, 283 (1884). Rbmsbn and Ksibb, 
Am. Chem. Jour., 4, 154 (1883); 5, 424 (1884). Lbdb, Chem. New, 48, 25 
(1883). 

^* CzAMiciAN and Btubsbl, BerichU, 46, 3894 (1912). 

17 Englib and Wni>, BerichU, 30, 1669 (1897). Enolb, Rev. gSn de Chim. 
pure et app., 6, 288 (1903). 



liS2 CATALYSIS IN ORGANIC CHEMISTRY 46 

Then in contact with the oxidisable subetance, B: 

A^. +B — A:0 + B:0. 

\0 stable >tabl« 

unstable 

The temporary formation of the combination, Af^ . , is the deter- 

X) 

mining cause in the oxidation of the substance B, which would not 

otherwise have taken place. 

In the absence of B, the second reaction would have taken place 
with the aid of a second molecule of A, thus: 

AC .+A«2(A:0). 

\o 

Whenever this latter reaction is sufficiently slow, the imstable 
peroxide can be prepared, by the action of oxygen on the auto-oxidiser 
alone, and may be kept for a time. Thus turpentine shaken with a 
large volume of air, forms a peroxide which, later on in the absence 
of air, can decolorize indigo, cause guaiac tincture to turn blue, or 
liberate iodine from potassium iodide. 

The auto-oxidiser. A, is not a catalyst, since it oxidises in pro- 
portion to its own mass, and since it does not emerge xmchanged from 
the reaction which it has caused. 

152. Oxidation Catalysts. Let us suppose that in the case of 
the auto-oxidiser. A, opposed by the oxidisable substance, B, that the 
latter can be oxidised not only at the expense of the imstable 

peroxide, A^ • , but also by reducing the stable oxide, A:0, we will 

then have the succession of reactions: 

/^ 

A + O, — AT • 

\0 

^ +B — AO + BO 



% 



AO + B — BO + A 



regenerated 

Thus the auto-oxidiser would be entirely regenerated and could 
again serve as a carrier of the free oxygen to the oxidisable substance. 
A limited amount of A could serve to oxidise an unlimited amoimt of 
B: A would then be an oxidation catalyst 



47 THE MECHANISM OP CATALYSIS 164 

153. This condition is realized by cerium salts with glucose in 
alkaline solution. A cerium salt, dissolved in the presence of potas- 
sium carbonate, is a colorless auto-oxidiser. We have: 

Ce(0H)3 + 0, + Ce(0H)3 = Ce(OH),.O.O.Ce(OH), 

uniUbla peroxlds 

Water reacts wiUi this compound: 

Ce(OH), .0.0. Ce(OH), + H,0 — 

Ce(0H)4 + Ce(OH),.O.OH . 

ocrlo hydroxide blood red 

The blood-red peroxide, when brought into contact with an 
oxidisable substance, such as potassium arsenite, oxidises it, returning 
to the state of the stable yellow eerie hydrate. There has been no 
catalysis. But if glucose is added, the eerie hydrate oxidises the 
glucose, being itself reduced to cerous hydroxide which can re- 
commence the cycle of reactions. This is catalysis.^* 

It is in this manner that small amoimts of manganous salts can 
cause the direct oxidation of unlimited quantities of pyrogallol or 
hydroquinone.** 

154. Platinum and Related Metals. The activity of platinum 
and related metals can be explained by a similar mechanism (243). 
In contact with oxygen, a sort of unstable peroxide is produced on 

the surface of the metal, comparable to the Af . of the auto- 

oxidisers. With an oxidisable substance, B, there is production of 
BO and AO, but the unstable AO oxidises another molecule of B to 
form BO and free A. Under these conditions the platinum would 
serve to render the oxygen atomic, and since the platinum is regen- 
erated in the course of the reaction, the cycle can be repeated 
indefinitely. 

The result is that the use of the platinum not only serves to lower 
the otherwise high temperatiu'e required by certain oxidations (e. g. 
of hydrogen or carbon monoxide) but also to realize other oxidations 
which can not be accomplished by molecular oxygen at any tempera- 
ture whatsoever, for example, the liberation of iodine from potassiiun 
iodide, which is effected in the cold by aerated '^ platinum black, or 

^> Job, Arm, Ckim, Phy8,, (7), ao» 207 (1900). Compt, rend., 234, 1052 
(1902); Z36, 45 (1903). 

^» Bmbtband, Bull, 80c. Chim^ (3), 17, 578 and 619 (1897). Ynj^BBS, Ibid,, 
(3), 17, 675 (1897). 

30 Enolb and Wohles, Z. anorg, Chem., 29, 1 (1901). 



166 CATALYSIS IN ORGANIC CHEMISTRY 48 

the production of nitric acid from ammonia, by hot platinum sponge. 
These fixations and liberations of oxygen take place at the surface 
of the metal and, for that reason, the catalytic power is proportional 
to the extent of that surface: it is immeasurably greater for platinum 
sponge, and especially for the black, than for the metal in foil or 
wire. 

155. General Explanation of Catalysis. The idea of a tem- 
porary unstable combination has served in explaining readily the 
mechanism of reciprocal catalyses (146), of induced catalyses (150), 
and also of catalyses in the strict sense of the term, such as direct 
oxidations (152). This notion can be generalized and applied to all 
sorts of catalyses. 

The formation and decomposition of intermediate compounds 
furnished by the catalysts usually correspond to a diminution of the 
free energy of the system and this diminution by steps is frequently 
much easier than the inunediate direct diminution, somewhat as the 
use of a staircase facilitates a descent. Ordinarily these successive 
step-downs take place quite rapidly, though rapidity is not a neces- 
sary condition of catalysis. 

These intermediate compounds can be isolated in a sufficiently 
large number of cases for us to generalize the idea and assume their 
formation in cases in which we can not prove their existence. 

156. Catalyses in which the Intermediate Compounds can be 
Isolated. Berthelot has pointed out well defined examples in the 
decomposition of hydrogen peroxide by alkalies and by silver oxide. 
We will cite some other examples belonging to very different types. 

Chlorination of Organic Compounds. In order to facilitate the 
direct chlorination of a liquid organic compound, iodine is dissolved 
in it. The chlorine unites with it to form iodine trichloride, IC1„ 
which could be isolated if the iodine were alone, but which, finding 
itself in contact with the organic substance, gives up chlorine to it 
returning to the lower state of iodine monochloride which the free 
chlorine transforms into the trichloride, this process being repeated 
again and again, thus: 



ICl, + MH =- HCl + MCI + ICl 
ICl + 01, — ICl,. 



It can be proved that the chlorination is proportional to the weight 
of the iodine trichloride. When the operation is carried on with a 
continuous current of chlorine, the trichloride is constantly re- 
generated and we have catalysis (278). 

157. The mechanism is doubtless the same for all of the anhydroiLS 



49 THE MECHANISM OF CATALYSIS 169 

m^tcd chlorides which are used as chlorine carriers in direct chlorina- 
tion (283). The intermediate products are easy to perceive in the 
case of the chlorides of antimony, thalliwn, molybdenmn, etc., where 
several different degrees of chlorination are known of which the 
highest are formed by direct action of chlorine, and which give up 
chlorine to the organic substance, returning to the lower stages which 
again take up chlorine. 

It is harder to see in the case of aluminum chloride, for which, 
by analogy, we must also assume a higher chloride, possibly due to 
the supplementary valencies of the chlorine atoms.*^ 

158. Manufacture of Sulphuric Acid. The manufacture of 
sulphuric acid in the lead chamber process employs, as catalyst, nitric 
oxide which intimately mixed with the reactmg gases (sulphur di- 
oxide, oxygen of the air, and water vapor) serves to render rapid 
the reaction which would otherwise take place slowly. The produc- 
tion of an intermediate product is doubted by no one although there 
is not entu*e agreement as to the true nature of such compound. 

159. Action of Sulphuric Acid on Alcohol. The mechanism 
of the action of concentrated sulphuric acid on alcohol is well known 
and is designated by the name of Williamson's reaction.** The first 
reaction is the production of ethyl sulphuric acid: 

CH,CH,OH + H,SO^ — H,0 + CH3CH, . . SO,H. 

The latter, at 140^, reacts with a second molecule of alcohol to 
form ether, regenerating sulphuric acid: 

CH,CH, . . SO,H + CH3CH3OH - H,SO^ + (CH,CH,),0. 

The sulphuric acid can again form ethyl sulphuric acid and so on 
ui4efinitely, since the temperature is high enough to cause the elimi- 
nation of the water along with the ether. Theoretically the action 
should continue indefinitely: it is a well defined case of catalysis. 
But a portion of the sulphuric acid is reduced to sulphur dioxide 
gradually diminishing the amount of the acid. 

If the mixture is heated higher, towards 160-170^, the ethyl sul- 
phuric acid is rapidly decomposed into sulphuric acid and ethylene: 

CH3CH, . . SO,H — H3SO4 + CH, : CH,. 

The regenerated sulphuric acid can repeat the reaction on the 
alcohol and hence is a catalyst for the formation of ethylene from 

^ It is possible to conflider this a case of the Fbudbl and Cbatts reaction, 
the aluminum chloride combining with the hydrocarbon to form an intermediate 
complex which reacts readily with Cl-Cl as it does with CIR. — E. E. R. 

** WmjAMSON, /. Chem. Sac, 4, 106, 229 and 350 (1852). 



160 CATALYSIS IN ORGANIC CHEMISTRY 50 

unlimited amounts of alcohol and can continue this fimction bo long 
as it is not too much diminished by reduction to sulphur dioxide. 
This reduction is more serious in this case as the reaction temperature 
is higher. 

160. Hydrogen Peroxide. In the catalytic decomposition of 
hydrogen peroxide by alkalies and alkaline earths, imstable inter- 
mediate compounds are plainly formed and can be isolated.** 

The intermediate steps are equally visible in many catalyses 
brought about in gaseous and liquid media by solid catalysts. 

161. Squibb's Method. A fine example is the method of Squibb 
for the preparation of acetone" (837). 

If acetic acid vapors are passed over calcium carbonate heated 
to 400^, calcium acetate is produced with the liberation of carbon 
dioxide. If the acid is discontinued and the temperature is raised 
to 500°, the calcium acetate is decomposed, regenerating the car- 
bonate and liberating acetone: 

At 400° 2 CHaCOaH + CaCOs - CO, + H,0 + (CH,CO,),Ca 
At 500° (CH3CO,) ,Ca — CaCO, + CH3 . CO . CH,. 

If the acetic acid is passed over the calcium carbonate at 500°, 
it is evident that the first reaction will tend to take place with the 
formation of calcium acetate, but this would decompose immediately 
to form acetone: the calcium carbonate would then be a catalyst 
(839), the reaction being: 

2 CH,COaH « CO, + HjO + CH, . CO . CH,. 

162. Catalytic Oxidation by Copper. If a current of oxygen 
is passed over copper heated to 250°, a layer of oxide is formed: 
if the vapors of an organic compound, such as an aliphatic hydro- 
carbon, are passed over the copi}er so oxidised, at the same tempera- 
ture, they are immediately oxidised with the production of water, 
carbon dioxide, etc., and with regeneration of metallic copper. If 
the hydrocarbon vapors and the oxygen are sent together over the 
copper at the same temperature, there is production of the oxide and 
immediate reduction of the oxide by the hydrocarbon; the copper 
functions as a catalyst. The total heat of oxidation may be great 
enough to carry the metal, on the surface of which it is taking place, 
to incandescence.'^ It is easy to see that copper oxide is the inter- 
mediate step. 

** ScHdNK, Annalen, zga, 257 (1878) and 193, 241 (1878). Bbbthslot, Ann, 
Chim. Phys,, (5), ax, 153 (1880). 

** Sqxtibb, /. Amer, Chem. 80c., 17, 187 (1895) and x8» 231 (1886). Conrot, 
J. 80c, Chem. Ind., ax, 302 (1902). Rev, gen. Sc, 13, 563 (1902). 

*" Sabatibr and MAn.HB, Compt. rend., 143, 1394 (1905). 



51 THE MECHANISM OF CATALYSIS 166 

163. Action of Nickel on Carbon Monoxide. Another example 
of the same kind is furnished by the destruction of carbon monoxide 
by nickel at SW. 

Carbon monoxide acting on reduced nickel around 100^, produces 
nickel carbonyl, Ni(C0)4. This warmed to about 160"^ decomposes 
completely into carbon monoxide and nickel, while from 250^ to 300^, 
it decomposes entirely differently, into nickel, carbon, and carbon 
dioxide: 

Ni(CO), — Ni + 2C + 2C0,. 

If carbon monoxide is passed over nickel at 150^, there appears 
to be no action since the nickel carbonyl that is formed is decomposed 
immediately, in place, into carbon monoxide and carbon. If the 
operation is carried on at 300^, there should still be the production 
of nickel carbonyl but it is at once decomposed into carbon dioxide, 
carbon, and nickel. The regenerated nickel can carry on the trans- 
formation of carbon monoxide into carbon and carbon dioxide 
indefinitely. 

164. Catalyses in which the Intermediate Compounds can not 
be Isolated. In the cases given above, the intermediate products 
which serve as stepping-stones for the reaction can be readily ob- 
served and even isolated as well defined chemical compounds, but in 
more numerous cases, these intermediate steps are difficult to per- 
ceive and it is only by analogies that we can surmise their nature 
with more or less uncertainty. 

165. Hydrogenation by Finely Divided Metals. The catalytic 
r61e of finely divided metals, nickel, copi}er, platinum, etc., in direct 
hydrogenation is easily explained by the assumption of unstable hy- 
drides on their suj'faces.^* Such condensation of hydrogen actually 
takes place to a certain extent, as we have seen above (136), and 
particularly with palladium, a really definite combination takes 
place in the cold. This has only a feeble dissociation pressure and 
has been assigned the formula, PdsHg, by Dewar.^^ 

** According to Willstatisb and WALDSCHMn>T-LBiTZ (Berichte, 54, 120 
(1921) ) oxygen must be present for hydrogenation to take place. They assume 
that the platinum combines with the oxygen first to form a sort of peroxide 
which then unites with the hydrc^n: 

/O /O H\ /O 

Pt + Oi -» Pt • and Pt • + Hi •=> Pt • 

\0 \0 H/ \0 

This peroxide hydride is the active intermediate compound, passing its hydrogen 
on to the substance to be hydrogenated and taking up more. — £. E. R. 
«^ DiWAB, Chem. News, 76, 274 (1897). 



166 CATALYSIS IN ORGANIC CHEMISTRY 62 

The hydrogen thus combined with palladium is able to produce 
many reactions which free hydrogen can not. It combines directly 
in the cold and in the dark with chlorine and with iodine as well as 
with oxygen.** It reduces chlorates to chlorides, nitrates to nitriteSi 
ferric salts to ferrous, mercuric to mercurous, potassium ferricyanide 
to ferrocyanide, indigo blue to indigo white, sulphur dioxide to hydro- 
gen sulphide, and arsenic trioxide to arsenic.** It transforms benzoyl 
chloride into benzaldehyde and nitrobenzene into aniline.** 

166. Hydrogen occluded by platinum produces analogous effects.*^ 
Thus when the vapors of nitrobenzene are directed onto platinum 
black previously charged with hydrogen, all the hydrogen which is 
present is utilized in the production of aniline. If at this moment, 
more hydrogen is introduced, a new fixation takes place followed by 
a further reduction of nitrobenzene. 

If the hydrogen and nitrobenzene vapors arrive simultaneously, 
there will be continuous reduction of the latter; the platinum is a 
hydrogenation catalyst. 

The catalysis appears to be a consequence of the occlusion of the 
hydrogen, that is to say, of the formation of a sort of combination 
of the hydrogen and the metal and the use of platinum as a catalyst 
is advantageous since the interchange of gases is rapid with it. 

Palladium, although it absorbs much more hydrogen, is usually 
inferior to platinum, probably because the hydrogen is not given up 
rapidly enough to the molecules to be hydrogenated. 

167. Copper, iron, cobalt, and especially nickel, reduced from 
their oxides are still more advantageous, although they can retain 
only small amounts of free hydrogen, probably because the forma- 
tion and decomposition of the hydrogen addition products are much 
more rapid. 

With nickel, the process goes on as if there were formed, on the 
surface, an actual imstable hydride capable of liberating hydrogen 
in the atomic condition and consequently more active than the original 
molecular hydrogen. The facts lead even to the idea that there are 

Ni— H y^H 

two stages in the fixation of hydrogen such as i^: ^ and Nic ^i 

Ni — ^H \H 

the latter more active combination being formed by metal reduced 
from the oxide below 300^ and capable of more kinds of work. The 
former, less active combination, would be produced by nickel reduced 
above 700^, or made from the chloride and able to hydrogenate ethy- 

*• BoRTGEB, Berichte, 6, 1396 (1873). 

** Gladstons and Tubb, Chem, NexM, zi* 68 (1878). 

*<> KoLBB and Sattzeit, /. prakt, Chem., (2), 4, 418 (1871). 

*^ Gladstons and Tribb, loc. cU. Cooxa, Chem. Newt, 58, 1(^ (1888). 



53 THE MECHANISM OF CATALYSIS 170 

lenio compounds, nitriles, and nitro bodies but not the aromatic 
nucleus. 

The catalytic hydrogenation of an ethylene hydrocarbon would 
be represented by: 

H, + Ni, — Ni,H,. 
Ni,H, + C,H, — C A + Ni,. 

The regenerated nickel would continue indefinitely to produce 
this effect so long as the hydrogen and ethylene continued to arrive 
simultaneously. 

168. If finely divided metals with free hydrogen give quickly 
fonned and readily decomposable unstable hydrides, they should also 
be able to take hydrogen from substances which hold it only feebly 
and should be dehydrogenation catalysts. In general, experiment 
has verified this prediction (651). 

169. Dehydration by Anhydrous Oxides. The dehydration of 
alcohols by certain oxides, as alumina, thoria, etc., can be interpreted 
readily by a close analogy to Williamson's reaction. 

These oxides can be tv^arded as the anhydrides of metallic hy- 
droxides capable of exercising the acid function, whether exclusively 
acid as with silicic or titanic acid, or either acid or basic (hydroxides 
of aluminum, thorium, chromium, etc.). Thus with alimiina, the 
alcohol vapor would give an imstable aluminate which in contact with 
alcohol would decompose to give ether, or at a higher temperature 
would immediately decompose evolving ethylene; the regenerated 
alumina would be able to carry on this reaction indefinitely: 

AliOi + 2CnH,^i.0H - H,0 + Al,0»(OC,H,«+i), 
Then 2CjaK+i.0H + Al,Oj(OC»HfcH.i)« - 2 (CJ«^0»O + A1,0,(0H), 

ethflr 

and AItOt(OH)i - HjO + AltO* 

or Al^(OCnBu+i)t - 2C,H,. + AljCCOH), 

bydrooArbon 

which would be immediately followed by the dehydration of the 
alumina. 

Such alcoholates can be isolated in various ways, for example, 
aluminum ethylate, which is decomposed cleanly into ethylene and 
alumina.** 

In the case of methyl alcohol, only the first sort of reaction is pos- 
sible, but in most other cases the other takes place exclusively.** 

170. It would be the same way with thoria which would furnish 
with alcohol vapors, a sort of thorium alcoholate which the heat de- 

** QLADSTomi and Tsm, Jour. Chem, Boe., 42, 5 (1882). 

** Sabatib and ybiusm. Awn, Chim. Phyt., (8), so, 840 (1910). 



171 CATALYSIS IN ORGANIC CHEMISTRY 54 

composes into an ethylene hydrocarbon and thoria, which is capable 
of reproducing the same effect indefinitely. If this is the case, this 
sort of eater would be capable of reacting chemically with various 
substances with which it is brought into contact and experiments 
have boimtifully confirmed the predictions made by Sabatier and 
Mailhe on this point.'^ 

In contact with thoria, alcohol vapors react directly with hydro- 
gen sulphide to give mercaptxma (743), with ammonia to form amines 
(732) , with phenols to produce mixed ethers (789) , and with aliphatic 
acids to yield esters (762). 

171. Decomposition of Acids. In the decomposition of aliphatic 
acids by anhydrous oxides it is frequently easy to perceive the inter- 
mediate compound which serves as a stepping stone in the reaction; 
namely, the salt formed by the acid and the oxide. It appears un- 
decomposed at temperatures lower than those used in the catalysis, 
as is the case with lime and zinc oxide (841). At a higher tempera- 
ture the salt is inmiediately decomposed to form the ketone. 

This intermediate formation ceases to be apparent when the acid 
is passed over the oxide at a higher temperature, because the forma- 
tion of the salt is then balanced by its rapid destruction. For certain 
oxides, as thoria and titania, it can not even be perceived since, 
doubtless, the formation does not take place at a lower temperature 
than the decomposition, but the analogy is so close that we can not 
fail to assume similar mechanisms with all of the oxides. 

172. In the decomposition of formic acid by metals or oxides 
(821), the intermediate compounds would be formed either from the 
hydrogen (passing over the metals), or from the carbon dioxide 
(fixed by the zinc oxide), or from the formic acid itself giving with 
the oxide a formate the decomposition of which would vary according 
to its nature. The molecule of this acid is a structure with little 
stability, tending to decompose in the two directions, into CO + H2O 
or into CO2 + H2 ; the affinity of the catalyst giving a transient com- 
pound, decides the direction. 

173. The Friedel and Crafts Reaction. The catalytic activity 
of anhydrous aluminum chloride in the Friedel and Crafts reaction 
(884) can be explained by the production of a temporary combination 
between the chloride and the organic material. Thus with aromatic 
hydrocarbons, we would have: 

CeRsH H- AlCl, - HCl + AI^ 

\C.R, 

'^ Sabaths and Mailhb, Compt. rend., iso, 823 (1910). 



65 THE MECHANISM OF CATALYSIS 176 

The latter compound would react immediately on the halogen 
derivative present and we would have: 

^Cl, 
Alf + R'Cl — AlCl, + R'.C.R^. 

The regenerated aluminum chloride would react again with the 
hydrocarbon and the same reactions would be repeated. It is then 
a catalyst and a small amoimt of the salt should effect the trans- 
formation of an unlimited amoimt of the mixture. This is in fact 
what takes place in some cases where the aluminum chloride can con- 
dense a hundred times its own weight of benzene with other molecules. 

174. Practically; it is often necessary to employ large amounts 
of the almninum chloride, sometimes even several times the weight 
of the aromatic hydrocarbon. For this reason some chemists have 
questioned the catalytic r61e of the chloride. It is, however, not to 
be doubted, as the necessity of sometimes using such large amounts 
of the catalyst is due either to the tardiness of the reaction in some 
cases and the desire to hasten it by providing for the formation of a 
large amount of the required intermediate compound or, in other 
cases, to the fact that the aluminum chloride forms stable combina- 
tions with some of the reactants which withdraw a portion of it from 
the reaction. The reality of the formation of addition products of 
the aluminum chloride with the organic compounds has been estab- 
lished by Gustavson who has been able to isolate an addition product 
with benzene, an orange colored oil, AlCl,.3CeH«, decomposable by 
water,^^ and in the case of the mixture of benzene and ethyl chloride, 
AlClg. (C2H4) 2.3CeH0, which heat dissociates into benzene and 

.CI 



Al< 



^ , which is stable and serves as catalyst for the trans- 

^(CACl), 
formation of the mixture.'* 

175. Action of Acids and Bases in Hydrolysis. In the de- 
compositions by addition of water, or hydrolyses, such as the saponi- 
fication of esters by strong mineral acids (313), or by strong bases 
(318), the inversion of cane sugar, the decomposition of glucosides 
(327) , or of acetals and, inversely, in the production of esters in pres- 
ence of small amounts of mineral acids (749), the active factors of 
the catalysis appear to be the ions resulting from the electrolytic dis- 
sociation of the acid or base*^ The activity of the catalyst is closely 

** Gustavson, Berickte, 11, 2151 (1878). 

^ Gustavson, Compt. rend., X36, 1065 (1903); 140, 940 (1906). 

*Y van't B.arr, Legons Chim. Phys^ 1898, III, 140. 



176 CATALYSIS IN ORGANIC CHEMISTRY 56 

connected with the amount of this dissociation and the velocity is 
proportional to the number of free ions in the solution. 

176. In saponifications catalysed by solublet bases, the active 
factors are the hydroxyl tans resulting from the electrolytic dissocia- 
tion of the base and we are justified in believing that the attack on 
the molecule of ester, ROA, derived from the oxy-acid AOH, is the 
work of the OH ions derived from the base. Thus with caustic 
potash we would have: 



ROA + 



flftor 



fOH 
+ [ — ROH + 

K I aleohol 




The ionized salt, AOK, is formed in the solution, but as the corre- 
sponding organic acid, AOH, is only slightly dissociated into ions, 
water hydrolyzes the salt to give: 

OA] fOHl 

+ Uh,o-aoh+ + 

E j ^ [k j 

The acid, AOH, is thus liberated and the ions of the original caus- 
tic potash are free to recommence their catalytic action. 

In the saponification of esters by acids it is the hydrogen ions that 
cause the effect. Thus with hydrochloric acid, we have: 




But there is immediate reaction with water to give: 

+ + 



-}+H,0 — AOH + 

Clj idd 



H 

CI 



The regenerated ions of the initial molecule of hydrochloric acid 
can repeat the reaction and so indefinitely. Esterification is brought 
about according to the same mechanism but in the inverse direction. 

178. The velocity of a hydrolysis of this sort is proportional to 
the number of ions that are active in producing it. With the strong 
acids at such dilutions that they may be regarded as completely dis- 
sociated, the effect will be independent of the nature of the acid and 
proportional to the concentration only. This has been verified for 
hydrochloric, hydrobromic, hydriodic, nitric and chloric acids.** It 

M O&FWJjJi, J. prakt. Chem^ (2), 98, 449 (1883). 



67 THE MECHANISM OF CATALYSIS 180 

is the same way with strong soluble bases, potassium, sodiumi 
bariiun, and calciiun hydroxides in sufficiently dilute solutions.** 

179. Catalysis in general appears to be the result of purely 
chemical phenomena accomplished by the aid of the catalyst which 
gives, with one of the elements of the primitive system, a temporary 
unstable combination, the decomposition of which, or the reaction of 
which, with one of the other reactants, determines the transformation 
of the system, the catalyst being regenerated in its original condition 
and able to repeat the reaction indefinitely. 

180. Ostwald has criticised the conception of the formation of 
intermediate compounds because it does not rest on a sufficiently 
exact knowledge of the reactions and because it would be further 
necessary to prove that the succession of reactions assumed requires 
less time than the direct reaction, and adds that no theory is of 
value in the absence of exact measurements. 

To tell the truth, we do not know much more as to the true nature 
of the absorption of gases and vapors by porous catalysts or even 
by wood charcoal; this absorption, or occZtmon, which is determined 
by a sort of selective affinity between the gas and the solid is a real 
solution penetrating to a certain depth in the solid and similar to 
the temporary combination which we have assumed, the differentia- 
tion of chemical and physical phenomena being always imcertain. 

The theory of catalysis by means of intermediate compoimds still 
contains many obscurities and has the fault of leaning frequently 
on the assumption of hypothetical intermediate products which we 
have not yet been able to isolate, but it is the only hypothesis that 
is able to explain catalysis in homogeneous solution and has the merit 
of applying to all cases. 

As far as I am concerned, this idea of temporary unstable inter- 
mediate compoimds has been the beacon light that has guided all my 
work on catalysis; its light may, perhaps, be dimmed by the glare of 
lights, as yet imsuspected, which will arise in the better explored 
field of chemical knowledge.^® Actually, such as it is, in spite of its 
imperfections and gaps, the theory appears to us good because it is 
fertile and permits, in a useful way, to foresee reactions. 

>* Rqchir, Annalen, aaS, 275 (1885). Ostwald, /. prakt Chem,, (2), 35, 
112 (1887). AmiHiNins, Zeit. phyt. Chem., x, 110 (1887). Bugabszkt, Ibid., 
8, 418 (1801).. 

«o Sabatub, BerichU, 44> 2001 (1911). 



18Qa CATALYSIS IN ORGANIC CHEMISTRY 58 

THEORIES OF CONTACT CATALYSIS 

By Wilder D. Bancboft 

180a. For purposes of discussion the theories of contact catalysis 
may be grouped under three headings: — 

1. Stoichiometric theory. 

2. Adsorption theory. 

3. Radiation theory. 

The stoichiometric theory is the one most commonly held because 
it involves nothing new or strange. According to this theory, one or 
more of the reacting substances forms with the catalytic agent a 
definite compound which then reacts in such a way as to give the 
final products. In the catalysis of hydrogen peroxide by mercmy, 
the intermediate formation of mercuric peroxide ^^ can be detected 
by the eye, because there is an intermittent building-up of a filrn 
which then breaks down, only to grow again. The formation of 
graphite is usually preceded by the formation of a carbide. The 
conversion of acetic acid into acetone** by passing the vapor over 
heated barium carbonate presimiably involves the intermediate for- 
mation of barium acetate. In the catalytic oxidation of carbon 
monoxide it is usually believed that there is an alternate oxidation 
and reduction of the oxides which act as catalytic agents. Hydrogen 
peroxide is said to oxidize cobaltic oxide to peroxide and to be de- 
composed catalytically by cobaltic oxide.** Nickel peroxide reacts 
quantitatively with hydrogen peroxide; but the resulting oxide is not 
converted back into peroxide by hydrogen peroxide and consequently 
does not decompose it catalytically. 

180b. While there are undoubtedly many cases of contact catalysis 
which come under this general head, it does not follow that this is 
the only type. It seems improbable that it would be so difficult to 
make carbon tetrachloride if the chlorine, which is absorbed by car- 
bon and thereby made active,** were present as a definite compound 
of carbon and chlorine. Oxygen absorbed by charcoal will oxidize 
ethyl alcohol to acetic acid** and ethylene to carbon dioxide and 
water, reactions which certainly are not characteristic of any known 

41 Bbxdig and von Antbopoff, Zeit. EUktrochemie, za, 585 (1906); von 
Antropoff, Jour, prakt, Chem., (2), 77, 273 (1908). 
*a Squibb, Jour. Am. Chem. Soc, 17, 187 (1895). 
*« Bayjmt, Pha. Mag., (5), 7. 126 (1879). 
** Damoisiau, Compt. rend., 73, 60 (1876). 
« Calvbbt, Jour. Chem. Sac., ao, 293 (1867). 



59 THE MECHANISM OF CATALYSIS 180d 

oxide of carbon. It is very important that we should decide in each 
particular case whether a definite intermediate compound is formed 
and, if so, what compound. Only in this way can we escape from the 
haziness which handicaps so much of the work on catalysis. For 
instance, it seems obvious to account for the hydrogenating power 
of pulverulent nickel by postulating the formation of an unstable 
hydride ; but the recent work of Professor Taylor of Princeton shows 
that no hydride is formed. It is easy to account for the different 
action of nickel, thoria, and titania on ethyl acetate by postulating 
the formation of intermediate compounds; but there is no experi- 
mental evidence that these hypothetical compounds would break 
down in the desired way if formed. To this day people are not agreed 
as to what intermediate compound is formed in the Deacon chlorine 
process. 

180c. The absorption theory does not postulate the intermediate 
formation of definite chemical compounds. The assumption is that 
the absorption of the substances to be catalyzed makes them more 
active chemically. This may occur in different ways. Since the 
reaction velocity is a function of the concentration, it was natural 
to ascribe the catalysis of oxyhydrogen gas by platinum to the in- 
creased concentration at the surface of the metal. This seems to 
have been disproved by the recent experiments in which oxyhydrogen 
gas is reported to be quite stable in presence of an alkaline solution 
whep under a pressure of three thousand atmospheres. This explana- 
tion will not sujffice to account for the cases in which the same sub- 
stance decomposes in one way in presence of one catalytic agent and 
in another way in presence of another. On the other hand, the in- 
crease in concentration must have an effect in some cases and it seems 
probable that this could be found most easily if one studies a re- 
action which takes place at a measurable rate in the absence of a 
catalytic agent, say ester formation, and if one takes an extremely 
non-specific absorbent, such as Patrick's silica gel. 

180d. Langmuir^® considers that an adsorbed gas is held chemi- 
cally by the unsaturated valences at the surface of the solid, thus 
forming a new type of compound which I have called indefinite 
compounds because they are not of the ordinary type and because 
no definite formulas can be written for them. In the case of the 
adsorption of argon by charcoal, for instance, we should have to 
write CzAr, where x varies with the mass of the charcoal and y 
with its siu*face as well as with the pressure and temperature. 
Chemical reactions may take place either between adjacent atoms 

«• Jour. Am. Chem. Soc, 37» 1139 (1915); 38, 1145 (1916). 



180e CATALYSIS IN ORGANIC CHEMISTRY 60 

on the surface or when gas molecules strike molecules or atoms on 
the surface. So far as the catalytic part is concerned this is much 
the same as the view of Debus.^' '^ If now a piece of platinum is 
placed in peroxide of hydrogen, the molecules of the latter will place 
themselves in such a position on the surface of the platinum that one 
oxygen atom of the peroxide is turned towards the platinum and as 
near to it as possible. The peroxide is polarized. But this has the 
effect also of bringing the oxygen atoms of different molecules of 
peroxide in such close proximity on the surface of the metal that 
they can combine to form common oxygen, the decomposition of the 
peroxide into water and oxygen and the development of energy being 
the consequence. The action of the platinum places the molecules 
of the peroxide in the position of reaction towards each other." 

180e. Langmuir has contemplated the possibility of a reaction 
between two adsorbed molecules and between one adsorbed and one 
free molecule. The second case is one in which a more effective col- 
lision is produced. This is a perfectly legitimate hypothesis. 
According to the kinetic theory the reaction velocity is proportional 
to the number of collisions between possibly reacting molecules; but 
it does not follow at all that two molecules react every time 
they collide. If a large number of collisions is necessary on an aver- 
age before a pair of molecules react, anything which would make 
these collisions more helpful might increase the reaction velocity 
enormously. The first question is then whether there is any evidence 
of ineffective collisions. This matter has been studied by Strutt^ 
who comes to the conclusion that a molecule of ozone reacts every 
time it strikes a molecule of silver oxide ; but that a molecule of ac- 
tive nitrogen collides with a molecule of copper oxide five hundred 
times on an average before they react, while two molecules of ozone 
at 100® collide on an average 6 x 10** times before they react. With- 
out insisting on the absolute accuracy of tiiese figures there is evi- 
dently plenty of margin for an increase in reaction velocity with 
ozone at 100® if one could produce more effective collisions. Lang- 
muir ^ finds that, at a pressure of not over 5 bars, and at 2770® K, 
15% of all oxygen molecules striking a tungsten filament react with 
it to form timgstic oxide, WO,. This coefficient increases at higher 
temperatures and at 3300® K about 50% of all the oxygen molecules 
which strike the filament react with it to form tungstic oxide. 

*^ Jour. Chem. 8oc., 53. 327 (1888) ; Cf. Ht^rNm, Jour, prakt. chem., (2), 
xo, 385 (1874). 

*• Proc. Roy. 80c., 87* A, 302 (1012). 

«• Jour. Am. Chem. 8oe., 35» 106 (1013); 38, 2270 (1016). 



61 THE MECHANISM OF CATALYSIS 180g 

180f . It is possible that a catalytic agent may cause one molecule 
to strike another amidships instead of head-on and may thereby 
increase the effectiveness of the collisions. It is not impossible that 
part, at least, of the effect of solvents on reaction velocity may be 
due to some such thing as this. If we adopt the views of Debus and 
Langmuir on oriented adsorption, all sorts of things become possible. 
If ethyl acetate, for instance, attaches itself to one adsorbent by the 
methyl group, to another by the ethyl group, and to a third by the 
carboxyl group, it might very well be that bombardment of the cap- 
tive molecule by free ones might lead to very different reaction 
products in the three cases. Such a suggestion is of very little value, 
however, unless it can be made definite. We do not know as yet 
whether ethyl acetate is actually adsorbed in one way by nickel, in 
another way by thoria, and in a third way by titania, nor do we 
know whether the difference in the manner of adsorption, assuming 
it to occur, is of such a nature as to account for the differences in 
the reaction products. 

180g. It is possible not to make an assumption as to the precise 
way in which adsorption takes place and merely to consider the sur- 
face of the solid as acting like a solvent. If the chemical potential 
of a possible reaction product is lowered in any way, there is an in- 
creased tendency for that reaction product to form.**^ If one treats 
a substance with a dehydrating agent, the tendency to split off water 
is increased. If a substance like alcohol can react in two different 
ways, we should expect a given catalytic agent to accelerate the re- 
action producing the reaction products which are adsorbed the most 
strongly by that catalytic agent."^ This appears to happen in the 
simpler cases. Ipatief"^ states that the decomposition of alcohol 
into ethylene and water in presence of heated alumina is due to the 
taking up of water by the alumina. That alimiina takes up water 
very strongly was shown by Johnson,'* who found that up to a cer- 
tain point alumina adsorbs water vapor as completely as does phos- 
phorus i}entoxide. Sabatier attributed the decomposition of alcohol 
into acetaldehyde and hydrogen in presence of pulverulent nickel to 
the tendency to formation of a nickel hydride. Both he and Ipatief 
assume the formation of definite compounds; but the argument is 
just as strong in case we postulate that the catalytic agent adsorbs 
the reaction products strongly instead of combining with them. An 

»o Mnxn, /our. Phya. Chem., x» 536 (1897). 
*^ BANCROiT, Jour. Phya, Chem., az, 591 (1917). 
«* BerichU, 37» 2986 (1904). 
*> Jour. Am. Chem. Soc,, 34> OH (1912). 



1801 CATALYSIS IN ORGANIC CHEMISTRY 62 

excesfi of the adsorbed reaction product should cut down the rate of 
reaction and that is the case. When working at high pressures, the 
first stage in the dehydration of alcohol in presence of heated alumina 
is the production of ether. When an equimolecular mixture of ether 
and water is passed over alumina at 4W, practically no ethylene is 
formed.*^* Engelder ■• showed that presence of water vapor decreased 
very markedly the rate of decomposition of ethyl alcohol by alumina. 
Titania causes alcohol to split both into acetaldehyde and hydrogen 
and into ethylene and water. Engelder showed that addition, of 
hydrogen to the alcohol vapor increased the relative yield of ethylene 
and addition of water vapor increased the relative yield of acetalde- 
hyde, though the difference was not as marked as one might have 
wished. A somewhat similar result appears to have been obtained 
unconsciously by Berthelot *• fifty years ago. He heated f brmic acid 
at 260^ without any specified catalytic agent and foimd that when 
only a third of the formic acid is decomposed the reaction appears 
to be 

HCO^H « CO + H^O. 

If all the formic acid is decomposed, the reaction is approximately 

2 HCO,H — CO + H,0 + CO, + H,. 

This imexpected result can only be true in case the reaction 

HCOjH = CO, + H, 

predominates during the latter part of the decomposition and this 
can happen only in case the original decomposition products check 
the initial reaction and thus permit the second reaction to come to 
the fore. The experiments by Berthelot should be rei}eated so as to 
make sure that they are right and that the suggested explanation is 
the true one. 

180h. While this seems very satisfactory, there are certain points 
which must not be overlooked. When making ethylene at Edgewood 
Arsenal during the war, it was found advisable to have a large amount 
of steam present with the alcohol vapor in order to make temperature 
regulation easier. This undoubtedly decreased the rate of decompo- 
sition of the alcohol; but that difficulty was overcome by working at 
a higher temperature. I find it very difficult to see how alumina can 
dehydrate alcohol in presence of a large amount of water vapor if 
the reason the alumina acts is because of its strong adsorption of 
water vapor. In spite of the fact that the theory of the selective 

«« Ipatiep, Berichte, 37* 2996 (1904). 

" Jour. Phya. Chem., 21, 676 (1917). 

«« Ann. Chim. Phya., (4), z8, 42 (1869). 



63 THE MECHANISM OF CATALYSIS 180j 

adsorption of the reaction products undoubtedly contains a great 
amount of truth, it must be admitted that, as now formulated, it is 
not the final word. It must be modified before it can be considered 
as satisfactory. If it breaks down temporarily in the simple case 
of the decomposition of alcohol, it is not surprising that we cannot as 
yet predict the decompositions of the esters by means of it. 

180i. The whole problem of catalysis has been put in a general 
but vague form by Baly and Erulla and Baly and Rice " who con- 
sider that we have a partial conversion of one or more reacting sub- 
stances into active forms through opening up fields of force by the 
rupture of normal valence or of contra-valences. The trouble with 
this is that it is as yet too vague to be of much value as a working 
hypothesis, though it makes an admirable starting-point. Methods 
must be devised for showing in each particular case what particular 
valences or contra-valences are ruptured as & preliminary step in 
the reaction. 

180j. The radiation theory postulates that the catalytic agent 
emits radiations which convert one or more of the reacting substances 
into active modifications. Miss Woker ^^ has given a sketch of the 
earlier speculations as to radiation. The only one which has sur- 
vived is that of Barendrecht,*^* and his calculations have been 
criticized severely by Henri.'® Kriiger'^ has attempted to account 
for a number of phenomena in homogeneous solutions by postulating 
infra-red radiation. This idea has been developed by W. C. McC. 
Lewis*' and applied to the change of reaction velocity with the 
temperature and to contact catalysis. More recently, Perrin*' has 
put forward similar views without making any reference to the work 
of others. Lewis believes that the catalytic agents emit infra-red 
rays which activate the reacting substance. This would seem to 
make it possible for a catalytic agent to act at a distance; but this 
difficulty can be avoided by assuming that the intensity of the infra- 
red radiation is so low that it is effective only when the distances 
are molecular. An interesting case comes up in homogeneous solu- 

»T Jour. Chem, Soc, xox, 1469, 1475 (1912). 

s< Die Katalyse, p. 60 (1910). 

»» Zeit. phys. Chem., 49, 466 (1904); 54, 367 (1906); Proc, Kon. Akad. Wet. 
Amtterdam, aa, 29 (1919). 

•0 Zeit. phye. Chem., 51, 19 (1905). 

•1 ZeU. ElektrochemU, if, 453 (1911). 

«s Jour. Chem. 80c., X05, 2330 (1914) ; Z07, 233 (1915) ; Z09, 55, 67, 796 
(1916); XXX, 457, 1036 (1917); 1x3, 471 (1918); 1x5, 182 (1919); System of 
Phyncd Chemistry, 3, 138 (1919). 

M FftBBiN, Ann. Physique, (9), xx, 5 (1919). 



180k CATALYSIS IN ORGANIC CHEMISTRY 64 

tions. Methyl acetate has a strong absorption band between 5 ft 
and 11 /i the hydrogen ion is supposed to emit wave-lengths over 
the range 1.1-11 /i, and hydrogen ion catalyzes methyl acetate 
solutions. Professor Rideal of the University of Illinois has shown 
that infra-red radiations corresponding to the absorption band of 
methyl acetate do accelerate the reaction between methyl acetate and 
water; but this would happen on any hypothesis. It has not been 
shown that the catal3rtic action of the infra-red rays supposed to be 
emitted by hydrogen ion corresponds quantitatively with the catalytic 
action of the hydrogen ion. This might be a difScult thing to estab- 
lish to the satisfaction of the doubters ; but there is a test which would 
probably be accepted as crucial by everybody. Heated nickel de- 
composes ethyl acetate into propane and carbon dioxide; heated 
thoria converts it into acetone, ethyl alcohol, ethylene and carbon 
dioxide; while heated titania changes it into acetic acid and 
ethylene.** If somebody would produce these three sets of reactions 
separately by means of infra-red radiations with no catalytic agent 
present, the radiation theory would have a standing which it does not 
have at present. Since alumina is very permeable to infra-red radia- 
tions and ferrous oxide is not,*^ the latter should be a very efficient 
catalytic agent according to the radiation theory. This has not been 
tested so far as I know. Tyndall ** states that gum arable is prac- 
tically impermeable to infra-red radiations. If this is true, gum 
arable should catalyze the hydrolysis of methyl acetate enormously 
if the radiation theory is sound. 

180k. This brief sketch of the theories of contact catalysis shows 
how unsatisfactory our present knowledge is. This is due to the in- 
accurate and incomplete way in which the single reactions have been 
studied. We do not know which cases involve definite intermediate 
compounds and which do not. When we are agreed that definite 
intermediate compounds are formed, we do not agree as to their 
nature. We talk about breaking normal valences or contra-valences; 
but we do not specify which valences or which contra-valences. 
When ethyl alcohol is decomposed by pulverulent nickel into acetal- 
dehyde and hydrogen, does molecular hydrogen split off or do the two 
hydrogens come off separately? If the latter happens does the first 
hydrogen come from the hydroxy 1 group or not? When ethyl alcohol 
is decomposed by alumina into ethylene and water, does water, hydro- 
gen, or hydroxyl come off first? It can hardly be water because it 
is possible to stop the reaction at the intermediate stage of ether, 

M Sabatibb and Mailee, Compt. rend,, i$2, 609 (1911). 

•» ZsiQMONDT, Dmglet'B PolyUch. Jour^ (6), 37» 17, 68, 108; 39, 237 (1893). 

^ FragmenU of Science: Radiant Heat and it$ Relatiom. 



65 THE MECHANISM OF CATALYSIS ISOn 

and it is probably not monatomic hydrogen because that is what 
happens with nickel. If the first stage is a splitting off of hydroxyl, 
does the other hydrogen come from the adjacent carbon atom giving 
ethylene direct or does it come from the same carbon atom, forming 
a substituted methylene, CH,CH| which then rearranges to ethylene? 
The decomposition of ether by alumina apparently must lead to 
2 CH3CH + H,0 as one of the intermediate stages. How does 
nickel decompose ether? 

180L In at least two instances it should be relatively simple to 
determine the reacting radicals. If we pass a mixture of ethyl ace- 
tate and hydrogen over pulverulent nickel, it is probable that some 
or all of the initial products will be reduced before they have time 
to react in the normal way. A study of the reaction products will 
therefore throw light on the probable mechanism of the reaction 
which occurs in the absence of hydrogen. If we obtained CH4 and 
HCOsCsHs, for instance, we should conclude that the original break 
had been into CH, and COjC^H,. If we found CHaCO,H and CHe, 
we should conclude that these were reduction products of CHaCO, 
and CsHg. If the reaction products were CH^, CsH^, and CO, or 
some reduction product of this last, we should undoubtedly assume 
that ethyl acetate splits simultaneously into CH„ CO, and CsHg. 

18Qm. If ether is passed over pulverulent nickel, the dissociation 
will probably be to Cfifi + CjH, or to C^Hfi + C,H4 + H. In 
the first case the final products will be 2 C^B.^ and H,0 just as with 
alumina. In the second case they are likely to be CH,CHO + C,H4 
-f- H„ though the ethylene and hydrogen may combine more or less 
completely to form ethane. 

180n. These two illustrations are sufficient to indicate the kind 
of work that ought to be done and the organic chemists will un- 
doubtedly be able to develop this suggestion in most unexpected ways. 

The following cases are worth considering, though it must not be 
assumed that the reactions run as written for one hundred per cent 
yield. 

With nickel we get the following decompositions of the esters: 

CH,CO,CH,CH, — CH,CH,CH, + CO, 
CH^CO^CH, — CH,CH, + CO, 
HCO,CH, - CHJ?) + CO, 

T^th thoria the decomposition is quite different: 

2 CH,CO,CH,CH, - CH,COCH, + CO, + (CA)tO 

- CH,COCH, + CO, + CjHaOH + C,H. 
2 CHaCOaCH, - CH3COCH, + CO, + (CH,),0 
2 HC0,CH, - HCHO4- CO, + (CH,),0 



1800 CATALYSIS IN ORGANIC CHEMISTRY 66 

With titama there is a third set of products: 

CH,CO,CH,CH, - CH,CO,H + C A 
2 CH,CO,CH, — 2CH,C0,H + C,H, 

HCO,CHa — HCO,H + CH, — CO + CH.OH. 

The decompositions are regular and characteristic with each catalytic 
agent and the molecules must break or slip at different points in the 
different cases. It would help a great deal towards formulating a 
theory of the behavior of these oxides if we knew exactly what hap- 
pened in each case. Of course, a study of this sort should include 
the chlorinated esters. There is some evidence to show that the de- 
composition may shift from one t3rpe to another with increasing sub- 
stitution of hydrogen by chlorine. 

180o. While we have no satisfactorily developed theories of con- 
tact catalysis at present, our theoretical knowledge in regard to the 
poisoning of catalytic agents is in good shape, though it is not sup- 
ported as yet by adequate experimental evidence. Since the reaction 
takes place in or at the surface, it follows that any substance, which 
cuts down the rate at which the reacting substances reach the cat- 
alytic surface '^ or which prevents them from reaching it, will decrease 
the reaction velocity and may destroy the catalytic action entirely. 
Berliner ** has shown that traces of fatty vapors from the air or from 
the grease on the stop-cocks will decrease the adsorption of hydrogen 
by palladium from nearly nine hundred volumes practically to noth- 
ing. Faraday ** has shown that traces of grease destroy the catalytic 
action of platinum on oxyhydrogen gas. De Hemptinne ^^ has appar- 
ently shown that carbon monoxide cuts down the adsorption of hydro- 
gen by palladiimi, though his method of presenting his results is very 
obscure. Harbeck and Lunge ^^ found that carbon monoxide inhibits 
practically completely the catalytic action of platinum on a mixture 
of ethylene and hydrogen. Schonbein ^' pointed out that the hydrides 
of sulphur, tellurium, selenium, phosphorus, arsenic, and antimony 
act very energetically in cutting down the catalytic action of platinimi 
on mixtures of air with hydrogen or ether. He considered that the 
hydride must decompose, giving rise to a solid film. This is not 
necessary in order to account for the phenomenon; but he seems to 
have been right in at least one case, for Maxted^* has found that 

•T TATum, Trans, Am, Electrochem. Soc^ 36 (1919). 

•• Wied, Ann,, 35> 003 (1888). 

** Experimental Reaearchea on Electricity, i, 185 (1839). 

TO Zeit. phys. Chem,, 2% 249 (1898). 

f^ Zeit, anorg. Chem,, z6, 50 (1898). 

72 Jour, prakt. Chem,, ag, 238 (1843). 

" Jour. Chem, Soc, 1x5, 1050 (1919). 



67 THE MECHANISM OF CATALYSIS 18Qr 

hydrogen sulphide is decomposed by platinum black with evolution 
of hydrogen, and that the platinum then does not adsorb hydrogen. 
Paal and Hartmann^* state that the catalytic action of palladium 
hydrosol and its adsorption of hydrogen are destroyed by metallic 
merciury or by the oxide of mercury. 

180p. Langmuir^* believes that oxygen prevents dissociation 
of hydrogen by a heated tungsten filament because it cuts down the 
adsorption of the hydrogen. 

180q. Hamed ^* has shown that the rate of adsorption ^^ of chlor- 
picrin by a charcoal which has been cleaned by washing with 
chlorpicrin is much greater at first than by a charcoal which has not 
been so cleaned, although the final equilibrimn is apparently about 
the same in the two cases. This is analogous to the evaporation of 
water when covered by an oil film. The oil cuts down the rate of 
evaporation very much but has practically no effect on the partial 
pressure of water at equilibrium. Taylor points out that normally 
the time of contact between a gas and the solid catalytic agent is 
extremely small and consequently anything which decreases the rate 
of adsorption will cut down the reaction velocity very much. 

180r. It is easy to see that the piling up of the reaction products 
will cut down the reaction velocity, if they prevent the reacting sub- 
stances from coming in contact with the catalytic agent. Bunsen 
apparently recognized this as early as 1857 for he is quoted^* as 
saying that it is only when the products of decomposition are removed 
and new matter is brought into contact that the reaction continues. 
This has been observed experimentally in the contact sulphuric acid 
process.^* The explanation that the decrease in the reaction velocity 
is due to a decreased adsorption of the reacting substances was first 
given by Fink,^^ who is the real pioneer in this line. Although the 
reaction between carbon monoxide and oxygen is practically . irre- 
versible at ordinary temperature, Henry "^ recognised that the pres- 
ence of the reaction product might slow up the rate of reaction and 
he proved his point by increasing the reaction velocity when he re- 
moved the carbon dioxide with caustic potash. Water vapor checks 

7« BerichU, $1, 711 (1918). 
7» Jour. Am. Chem. 8oc^ 3S, 2272 (1916). 
T« Jour. Am. Chem. 80c., 42, 872 (1920). 
77 Taylor, Trans. Am. Electrochem. 8oe., 36 (1919). 
7« Dbacon, Jour. Chem. 80c., 25, 786 (1872). 

7» BoDLANDB and EOPFIN, Zeil. Elektrochemie, 9, 566 (1908); Bebl, Zeit. 
anorg. Chem., 44^ 267 (1906). 

*o BoDBNsmN and Fink, Zeit. phya. Chem., 6o» 61 (1907). 
» PhU. Mag. (8), 9, 324 (1886). 



180s CATALYSIS IN ORGANIC CHEMISTRY 68 

the catalytic dehydration of ether *^ and of alcohol ^ and hydrogen 
cuts down the catalytic dehydrogenation of alcohol. 

ISOs. When catal3iric poisons are present or are formed during the 
reaction, the apparent equilibrium may vary with the amount of the 
cataljiric agent.** With only a small amount present, the catalytic 
agent will be poisoned before the reaction has run very far. In the 
hydrolysis of ethyl butyrate by enzymes, the reaction apparently 
rims to different end-points depending on the relative amounts of 
enzyme.** 

While our theoretical knowledge in regard to the poisoning of 
catalytic agents is fairly adequate, we know literally nothing except 
empirically in regard to the action of the so-called promoters. It has 
recently been found that the addition of small amounts of a substance 
which does not in itself have any very marked catalytic action may 
make the catalyst considerably more active. Such substances were 
called promoters in the patents of the Badische AniJin and Soda 
Fabrik, and the term is now in common use. Rideal and Taylor say: 
" Thus far no theory put forward to account for the acceleration of 
reaction by minute quantities of promoters added to the main catalyst 
material is completely satisfactory. A possible mechanism, which, 
however, has received no experimental test, may be advanced by con- 
sidering the case of ammonia synthesis from mixtures of nitrogen and 
hydrogen. Reduced iron is an available contact substance, the ac- 
tivity of which may be regarded as due to the simultaneous formation 
of the compounds, hydride and nitride, with subsequent rearrangement 
to give ammonia and unchanged iron. Or, maybe, the activity of the 
iron is due to simultaneous adsorption of the two gases. The par- 
ticular mechanism of the catalysis is unimportant for the present 
considerations. Now such bodies as molybdenum, tungsten, and 
uranium have been proposed, among others, as promoters of the ac- 
tivity of iron. It is conceivable that these act by adjusting the ratio 
in which the elementary gases are adsorbed by or temporarily com- 
bined with the catal3iric material to give a ratio of reactive nitrogen 
and hydrogen more nearly that required for the synthesis, namely, 
one of nitrogen to three of hydrogen. From the nature of the ma- 
terials suggested as promoters, it would seem that they are in the 
main nitride-forming materials, which on the above assumption of 
mechanism would lead to the conclusion that the original iron tended 

S3 Ipatibv, Berichte, 37> 2996 (1904). 

** Lbwis, Jour. Chem. Soc, 11$, 182 (1919). 

** BAScaon, Jour. Phya. Chem., 22, 22 (1918). 

t5 Kabtu Bud LocvBNHABT, Am. Chem. Jour., 34, 491 (1900). 



69 THE MECHANISM OF CATALYSIS 180a 

to adsorb or form an intermediate compowid with a greater propor- 
tion of hydrogen to nitrogen than required by the stoichiometric ratio. 
The catalytic activity of reduced iron as a hydrog^nation agent would 
tend to confirm this viewpoint. 

180t. ''In reference to this suggested mechanism it must be 
emphasized, however, that in such examples of ' promotion/ as re- 
quire only minute quantities of added promoter the activity is more 
difficult to understand. With the case of ammonia synthesis, the 
promoters are added in marked concentrations. It is difficult to 
realize, however, that 0.5 per cent of ceria or a concentration of one 
molecule of ceria among 200 molecules of iron oxide, in the example 
cited above in reference to catalytic hydrogen production, can so far 
' redress the balance ' of adsorption or combination as to produce the 
marked increase in activity of which it is capable. It is obvious that 
in this phase of the problem there lies an exceedingly fascinating field 
for scientific investigation, with the added advantages that, being 
practically virgin territory, the harvest to be gained therefrom should 
be rich and abundant." 

180u. Instead of the promoter changing the ratio of adsorption, 
it might be that the catalytic agent activates only one of the reacting 
agente or activates one chiefly, and that the promoter activates the 
other. Thus it might be, in the ammonia synthesis, that iron acti- 
vates the hydrogen chiefly so that we have hydrogenation of the 
nitrogen. The molybdenum might tend to activate the nitrogen 
giving rise to nitridation of hydrogen, or it might increase the activa* 
tion of the nitrogen. Such a state of things is not impossible theo- 
retically. When a dye -jceacts with oxygen under the influence of 
li^t, the li^t may make the ^o^cygen active, in which case the acti- 
vated oxygen oxidizes the dye, or the light may make the dye active 
in which case the activated dye reduces the oxygen. It is easy to 
decide this question by seeing whether the effective light corresponds 
to an adsorption band for the dye or for the oxygen. 



CHAPTER IV 

ISOMERIZATIONS, POLYMERIZATIONS, AND 
CONDENSATIONS BY ADDITION 

§1. ISOMERIZATIONS 

181. IsoMERiZATioNS^ that is to say, changes of structure effected 
within a molecule without modifying its composition, are often 
accomplished by the action of heat alone. 

As catalysts have frequently the effect of lowering the temperature 
of reactions, it can be foreseen that their use will permit, in many 
cases, of realizing an isomerization at a lower temperature, or causing 
it to go more rapidly. Experiment has often verified this prediction 
under very varied conditions. 

Strong mineral acids bring about a large number of isomerizations ; 
the concentration of the acid has usually a great influence on the 
direction of the transformation. The mechanism of the change can 
usually be interpreted by assuming the addition of water to the 
original compound under the influence of the acid ions followed by a 
dehydration, or the reverse. 

182. Change of Geometric Isomers. The transformation of 
fumaric add into maleic is brought about by a large number of cat- 
alysts, for example hydrobromic or hydriodic acids in hot concen- 
trated solution,^ hot hydrochloric add,* or hot dilute nitric add,* 

Bromine acts, in the cold, on maleic acid to give dibromsuccinic 
acid but, at the same time, a part of the maleic acid is changed to 
fumaric* 

Likewise, traces of iodine are sufficient to transform maleic esters 
into fimiaric.*^ 

If to a solution of maleic acid an equivalent amount of sodvum 
thiosidphate be added and then sulphuric acid, sulphur dioxide is 
evolved without appreciable separation of sulphur and 26% of firaiaric 
acid crystallizes out.® 

^ ExKULfi, Annalen, Supp, Band, z» 133 (1861). 

* KsKULfi and Strbckbr, Anndlen, aaa, 186 (1884). 

* ExKVhA, Annalen, Supp. Band, 2, 93 (1862). 

* FfeTBi, Annalen, 195, 40 (1879). 

■ Skraup, Monatsh,, za, 107 (1891). 

* Tanatar, /. Russian Phya. Chem. Soc, 43» 1742 (1912), C. A., 6, 1279. 

70 



71 CONDENSATIONS BY ADDITIONS 186 

When hydrogen sulphide is passed into solutions of lead, copper, 
or cadmium maleates, the maleic acid set free is changed to fiunaric.^ 

183. Citracomc acid warmed with dilute nitric acid,* or with con- 
centrated hydrobromic acid,* or with concentrated hydriodic acid,^* 
is changed into mesaconic acid. 

Warmed above 100^ with a concentrated solution of caustic soda, 
it gives mesaconic acid with a little itacordc.^^ 

Itacomc acid dissolved in a mixture of etiier and chloroform to 
which a few drops of a chloroform solution of bromine have been 
added, and exposed to sunlight, is transformed into mesaconic acid.^* 

Itaconic acid boiled with soda lye changes, almost entirely, into 
mesaconic.^* 

184. Small amounts of rdtrous add transform a number of cis 
ethylenic acids into their trans isomers, oleic into eUndic,^* hyprogaeic 
into gatdic,^^ erucic, CsH^CH : CH(CH,)iiCO,H, into brassidic.^* 

185. a-Bematdoodme in contact with hydrogen chloride or with 
crystallized pyrostdphvric acid is changed into fi-benzaidoxime}^ 
The reverse change is brought about by contact with dilute stdphvric 
add. 

186. Changes of Optical Isomers. Solutions of caustic soda can 
determine numerous stereo-isomeric changes in the sugar group and 
the same is true of solutibns of lime and baryta and even of pure 
water mixed with lead and zinc hydroxides.^* Olttcose, mannose and 
fructose, heated two hours under these conditions yield the same mix- 
ture of these three hexoses. In the cold and with concentrated alka- 
lies, the same isomerization takes place in five days. In the same 
way, galactose gives a mixture of sorbose, tagatose, talose and gal- 
tose.^* Similarly baryta water transforms gulose or idose into sor^ 
bose}* 

^ Skraitp, lac. cU. 

* GoTTLOB, Annalen, 77, 268 (1857). 

• Frma, Ibid., z88, 77 and 80 (1877). 
^0 Kekx7l6, Ibid., Supl., 2, 94 (1862). 

^^ Dbuslb, Ibid., a69, 82 (1892). Fima and Lanowobtht, Ibid., 304, lfi2 
(1899). 

12 Puna and Langwobtht, Ibid., 304, 152 (1899). 

^s Frma and K6hl, Ibid., 305, 41 (1899). 

" BotTDBT, Ann. Chim. Phys. (2), 50, 391 (1832). Lauimnt, Ibid. (2), 65, 
149 (1837). 

^^ Caldwbll and GdssMANN, Armalen, 99, 307 (1856). 

^* Haussxnbcht, Ibid., 243, 54 (1867). 

^f Bkkmanjk, BerichU, ao, 2766 (1887). 

^ LoBKT DB BsuTN and Van Ekbnsteik, Rec. Trav. Chim. Pays-Bas, 24, 
203 (1895) and 15, 92 (1896). 

^* Van ExBNsraiN and Blakksma, Ibid., 37, 1 (1908). 



187 CATALYSIS IN ORGANIC CHEMISTRY 72 

187. The acids derived from the hexoses are isomerized when they 
are heated to 135-150^ with an organic base that does not yield 
amides with the acids; quinoline or pyridine are usually employed. 
The new acid differs from the old only in the arrangement of the 
groups around the last asymmetric carbon atom. Furthermore, the 
isomerizations take place in both directions, reaching the same limit. 
Thus gluconic acid furnishes mannonic with quinoline and recipro- 
cally.'^ Likewise with pyridine we pass from arabonic acid (with five 
carbon atoms) to ribonic,*^ from lyxordc to xylonic,** and also from 
the dibasic acid, tcdomucic, to mvcic?* 

188. The sugars, glucose, laevulose, galactose, arabinose, and 
xylose, which are not susceptible of a molecular decomposition by the 
addition of water, present a special phenomenon known as mvltirota' 
tion; the rotatory power observed immediately after solution in water 
is much greater than that after some time.*^ 

Thus the rotation of glucose starts at 105^ and goes down to half 
of this, 52.5^.*^ The explanation is that there are isomeric molecular 
modifications of these various sugars, analogous to the three varieties 
that Tanret has been able to isolate for glucose.*' 

Of the three varieties, the one that is stable in dilute solution, 
called j8, has exactly the rotatory power finally foimd, 52.5^, another 
form a has the value 106^. The passage to the stable isomer takes 
place slowly in the cold, rapidly when hot, but is greatly accelerated 
by the presence of mineral acidaV 

189. dJdenthone on long contact with svlphitric add containing 
10% of its volume of water passes to Lmenthone.^^ 

190. Migrations of Double and Triple Bonds. laopropyl- 
ethylene, (CH,)2CH . CH : CH„ when heated under pressure at 480- 
500^ in the presence of anhydrous alumina^ is transformed into 
trimethyl-ethylene, (CH,)aC : CH . CH,." 

191. Eugenol, when boiled with amyl alcoholic potash, changes 
to isoeugenol, the direct oxidation of which furnishes vanilline: ^ 

so E. FiscHEBy BerichU, as, 801 (1890). 
*i FiscHBB and Fjurrr, Berichte, 34, 4216 (1891). 
ss FiscHBB and Bbombibg, Berichte, ag, 584 (1896). 
ss FiSGHSB and Mobbll, Berichte, ay, 387 (1894). 
s« DuBBUNrAUT, Ann. Chim. Phys. (3), x8, 105 (1846). 
s* Pabcus and Tollins, Anruden, 357, 160 (1890). 
s« Tanbbt, BuU. Soc. Chim. (3), %$» 105 and 349 (1896). 
S7 Erdmann, Jahresb., X855, 672. 
s< BiCKMANN, Annalen, 250, 334 (1889). 

s* IPATnr, /. Bunion Phys, Chem. 80c., 38, 63 and 92 (1906), C, 1906, (2), 
86 and 87. 

so ToMANN, BerichU, a4» 2871 (1891). 



73 CONDENSATIONS BY ADDITIONS 198 

.CH«CH:CH« .CHrCHCHi 

C3|H,-0CH. -* CtHa-OCH. 
^OH \)H 

192. The acetylene triple bond undergoes analogous transpositions 

under the influence of sodium or of alkalies. 

Ethyl-acetylene, CH, ..CH, . C i CH, heated with potash to 170^, 
changes to dimethyl-acetylene, CH, . C i C . CH,. '^ 

Inversely, disubstituted acetylene hydrocarbons are changed 

into true acetylenes when they are heated with sodixun, a 

part of the new hydrocarbon combining with the metal, 

e. g. methyl-ethyl-acetylene, CH, .0 . C . CH, . CH„ g^ves propyl" 

acetylene, CH, . CH, . CH, . C i CH." 

The same catalysts cause the transformation of allenic hydro- 
carbons into acetylene hydrocarbons and inversely. Thus diethyl- 
allene, CH, . CH, . CH : C : CH . CH, . CH„ which under the influ- 
ence of heat alone isomerizes into methyl-ethyl-butadiene, is changed 
by contact with metallic sodium into diethyl-aUylene, CH, .CH^- 
CH,.C : C.CH,.CH,. ^ 

Inversely isopropyl-acetylene, (CH,) ,CH . C i CH, heated above 
150^ with alcoholic potash, changes to dim^thyl-allene, (CH,),C :- 
C : CH,. •* 

193. Decyclizations. Cydo-propane is not changed to propylene 
by heat alone below 600^, but in the presence of platinum sponge, this 
change takes place in the cold and very rapidly at 100^. ^'^ 

The vapors of ethyl-cyclo-propane passed at 300-310^ over as- 
bestos impregnated with anhydrous alumina, are isomerized into 
methyl-ethyl-ethylene: 

CH,v 

I ;CH . CH, . CH, -* CH, . CH : CH . CH, . CH,. «• 
CH,/ 

CH,v 
Methylene-cyclo-propane, I C : CH„ passed over alumina at 

CH,/ 
350^ gives divinyl, CH, : CH . CH : CH,. " 

s^ Fawobsu, /. Rusnan Phys. Chem. Boc^ xg, 414 and 653 (1887) ; ao, 518 
(1888), C z887, 163. 

^ Fawobskt, /. prolbt. Chem., (2), 37, 387 (1888). BifiHAi^ BuU. 8oe. C^tin^ 
50, 029 (1888). 

** Mbbbhkovski, /. Russian Phys. Chem. 8oe., 45, 1969 (1914), C. A^ 8, 
1420. 

^ Fawobskt, /. prakt. Chem. (2), 37, 392 (1888). 

M Tanatab, Zeit. phys. Chem., 41, 735 (1902). * 

*« RoflEANOV, /. Russian Phys. Chem. See., 48, 168 (1916), C. A., zx» 454. 

*^ Mabkhkovski, Ibid., 45, 2072 (1914), C. A.. 9, 799. 



194 CATALYSIS IN ORGANIC CHEMISTRY 74 

194. Cyclizations and Transformations of Ring Compounds* 
Hydrobemamide when boiled with potash changes to amcaine: '* 

C.H. .CH : Nn^ C«H, .C.NH\ 

C.H5 . CH : n/ C«H« . C . NH/ 

195. The acetylenic pmacones when kept on the water bath with a 
4% water solution of mercuric sulphate, are rapidly and completely 
isomerized into ketohydrofiarfuranes. Doubtless there is at first 
addition of water to the triple bond and then dehydration of the glycol 
thus obtained: ** 

CO - CH, 

^C(OH)CiC.C(OH)(^ -♦ (CHa),:C C:(CHa), 

CH,/ \CH, \o/ 

196. In contact with maleic acid or with other acids, dimethyU 
ketazine isomerizes into trimethyl-pyrazoUne: *® 

CH|v yCHa CEU"CH*CHf\ yCEU 

)C:NN:CC -* |l ;CC 

CH,/ \CH, N — NH/ \CH, 

197. Cyclo'heptane, heated to 210^ with reduced nickel in an 
atmosphere of hydrogen, is transformed into methyUcyclo-hexane, 
and likewise cyclo-octxine gives dimethyUcyclo-hexane.^^ 

198. Sulphuric acid provokes many isomerizations among the 
terpenes. Thus pinene, warmed with sulphuric acid diluted with its 
own volume of water, is changed to a mixture of terpinolene, terpinene, 
and dipentene.** 

IJPinene dissolved in glacial acetic acid and warmed to 60-70^, 
isomerizes into IJimonene with evolution of heat, when 5% of phos- 
phoric acid is added.** Likewise phellandrene, on contact with sul- 
phuric acid, yields terpinene.^* 

Thujone is isomerized to isothujone when it is warmed for nine 
hours with sulphuric acid diluted with two volumes of water." 

In the presence of sulphuric acid, pseudo-ionone passes into the 
cyclic a- and fi-ionones. Thus a-ionone (artificial extract of 

s* FowNBS, Annalen, 54^ 364 (1845). 

s* DupoNT, Compt. rend^ 152, 1486 (1911) and 153, 275 (1911). 

«o CuRTius and FoBSTEBUNa, /. prakt. Chem. (2), 51, 394 (1895). 

«^ WmiSTATTBB and Kamrtaka, Berichte, 41, 1480 (1908). 

*> Armstbong and TnjxBN, Berichte, xa, 1754 (1879). 

«s Pbins, Chem. WeekbL, 13, 1264 (1916), C. A., zz, 586. 

^ Wallach, Annalen, 239, 35 (1887). 

*^ Wallach, Annalen, a86» 101 (1877). 



75 CONDENSATIONS BY ADDITIONS 201 

violets) is prepared by heating for 16 hours, 20 parts pseudo-ionone 
dissolved in 100 parts of water and 100 parts of glycerine with 2.5 
parts sulphuric acid. Concentrated sulphuric acid gives mainly 
jg-ionone. Phosphoric acid also may be employed.** 

199. Migration of Atoms. Migrations of halogen atoms are 
frequently effected by anhydrous aluminum chloride or bromide. 
Thus propyl bromide, CH, . CHj . CH^Br, boiled 6 minutes with 10% 
of aluminum bromide is completely transformed into isopropyl bro- 
mide, CH3 . CHBr . CHs ; while 4% of the salt will effect the change in 
24 hours in the cold.*^ The mechanism is apparently a separation 
into propylene and hydrobromic acid and a recombination of these to 
fonn isopropyl bromide. 

Propyl chloride is affected in the same way.** 

In the presence of anhydrous aluminimi chloride at 110^, acetylene 
tetrachloride, CHCI2 . CHCl,, changes partly into the unsymmetrical 
tetrachlorethane, CCl, . CH^Cl. *• 

By warming with 15 to 20% of aluminum chloride, a-bromnaph- 
thalene, dissolved in 3 or 4 parts of carbon disulphide, is transformed 
into jg-bromnaphthalene.** 

200. Mercwric chloride and zinc bromide greatly accelerate the 
isomerization of isohutyl bromide, (CH3)2CH .CHaBr, into tertiary- 
butyl bromide, (CHg),CBr." 

Rv 

Ethylene oxides of the type, C CHj, kept in contact with 

Rv 

zinc chloride, are isomerized into aldehydes, )CH . CHO. Thus 

R'/ 

ethylene oxide gives acetaldehyde.^* The same transformation is 
accomplished by anhydrous alumina acting on the vapor of ethylene 
oxide at 200^" 

201. Concentrated or dilute mineral acids frequently cause the 
migration of atoms in a straight chain of cyclic hydrocarbon or in a 
ring containing nitrogen. 

«• TiBMANN and KRtamt, Berichte, a6, 2603 (1893) and 31, 808 (1808). 

*'' Kkkul6 and Schroths, Berichte, 12, 2270 (1879). Gustavson, J. Rus- 
sian Phya, Chem. Soc, 15, 61 (1883). 

*« MouNETBAT, BuU. Soc. Chim. (3), ax, 616 (1809). 

«» MouNBTBAT, Ihtd. (3), zg, 400 (1808). 

w Roux, Arm: Chim. Phys. (6), xa, 344 (1887). 

■^ MicHABL, ScHARF, End Voicrr, /. Am. Chem. 8oc., 38, 653 (1016). 

^^ KASCHntSKi, /. Ru88ian Phys. Chem. 80c., 13, 76 (1881), C, z88z, 278. 
Erabsuski, Ibid., 34» 5^ (1002), C, zgoa, (2), 1005. 

** Ipatup and Lbontowitch, Beritche, 36, 2016 (1003). 



902 CATALYSIS IN ORGANIC CHEMISTRY 76 

The 1,2 dihydrotetrcunnes isomerize into the 1,4, when heated with 
alcoholic hydrochloric acid,** thus: 

^N ^Nv /NH-N^ 

\NH— N^eH. ^N ^N^iH4 

202. AcetylcMoraminobemene, CH, . CO . NCI . CeHe, is tranfl- 
formed into p.chloracetanilide, CH, . CO . NH . CeH^Cl, under the in- 
fluence of hydrochloric acid." The same acid changes hydraso- 
bensene into benzidene." 

CeH,— NH CeH^— NH, 

CeH.— NH C,H,— NH, 

203. Acids with a double bond in fiy position, and hydroxyl in the 
a, are changed by boiling with dilute hydrochloric acid into7-keto 
acids. Thus phenyl-^x-hydroxycrotonic acid, C^Hj . CH : CH .- 
CH (OH) . COOH, is changed into benzoyl-propionic acid, CeH, .- 
CO . CH, . CH, . COOH. The mechanism of this reaction has been 
variously explained.*' 

204. The aldoximea, R . CH : NOH, of the aliphatic series are 
changed to amides, R . CO . NH„ by warming with sulphuric acid. 
To explain this change it is sufficient to assume that there is first a 
dehydration of the oxime to the nitrile which is hydrated by the min- 
eral acid in the usual way to the amide. 

205. In contact with sulphuric acid, oximes of cyclic ketones are 
transformed into internal amides, or iso-oximes. Thus the oxime of 
cyclohexanone yields the lactam of e-^ii^ii^ocaproic acid: 

•CH, . CH,v yCH, . CH, . NH 

CH,C )C:NOH -* CH,( I 

\CH, . CH,/ \CH, . CH, . CO 

The concentrated acid, to which a little water or acetic acid has 
been added, is suitable for this reaction.** 

206. Alkaline solutions also can cause the migration of atoms. 
The potassium salt of diazobemene heated to 130^ with concentrated 
caustic potash is changed to the potassium salt of phenylnitrosamine^^ 

B« 8ioll£, /. prakL Chem. (2), 73, 299 (1906). 

*■ AcREB and Johnson, Am, Ckem. Jour., 37, 410 (1907). 

M ZiNiN, Amuden, 237, 376 (1865). 

•7 Fima, Annalen, agg, 20 (1898). TmnJi and Sui^bbgbr, Ibid., 3x9, 199 
(1901). Erlbnmbtbb, Jr., Ibid., 333, 205 (1904). BovGAUi^r, Aim. Chim, Phya. 
(S), 25, 513 and CompL rend., 257, 403 (1913). 

■* Wallach, Armalen, 32a, 171 (1900). 

** ScmiAUBB and Schmq>t, Berichte, aj, 522 (1994), 



77 CONDENSATIONS BY ADDITIONS 210 

/NO 
CaH,.N:N.OK -* CeH^.l^C 

\k 

207. Thiourea, CSCNH,),, on contact with a solution of ethyl 
nitrite, isomeriaes into ammonium isosulphocyanate, CSN . NH^.** 

208. In certain cases, finely divided metals, copper, nickel, etc., 
can bring about a migration of atoms, thus causing a change of func- 
tion. Thus unsatvrated alcohols are transformed into aldehydes or 
ketones in a way that is easy to explain. 

AUyl alcohol, CH, : CH . CH2OH, passed in the vapor form over 
reduced copper at 180-300^, is changed almost entirely into propionic 
aldehyde, CH, . CH2CHO, with only slight traces of acroleme, 
CH| : CH . CHO. The hydrogen produced by the decomposition of 
the alcohol by the copper is immectiately added to the double bond of 
the acroleme.*^ 

Likewise a-unsaturated secondary alcohols, R . CH : CH .- 
CH(OH) . R', mixed with hydrogen over reduced nickel at 19&-200^, 
are isomerized into the ketones, R . CH, . CHg . CO . R'. 



61 



§3. POLYMERIZATIONS 

209. Frequently several molecules of the same kind, having one 
or more double bonds, condense to a single molecule, which is called 
a polymer of the original molecule. The presence of a catalyst fre- 
quently causes such a change or accelerates its velocity. We will 
examine from this point of view: 

Hydrocarbons. 
Aldehydes. 
Nitriles and amides. 

Hydrocarbons 

210. Ethylene Hydrocarbons. Hydrocarbons of the ethylene 
series, CnH^ni frequently change into polymers of double, triple, or 
even quadruple, the original molecule yet retaining the same character 
as the original. 

Sulphuric acid, either concentrated or slightly diluted, frequently 
causes this polymerization. In fact, its action is complex as, besides 
polymerization, it can cause the addition of water to form secondary 
or tertiary alcohols and also the formation of acid or neutral esters 

^ Glaus, Anndlen, 279, 139 (1875). 

<^ Sabatub and SbNDBBiNB, Ann. Chim. Phys. (8), 4, 463 (1905). 

** DouBis, Compt. rend., 257, 55 (1913). 



211 CATALYSIS IN ORGANIC CHEMISTRY 78 

of sulphuric acid. With hydrocarbons of moderate molecular weight, 
there is principally the formation of alcohols and esters.** Thus 
sulphuric acid diluted with its own volume of water transforms tri- 
methyl-ethylene, (CH8)jC : CH . CHg, at 0*^, chiefly into dimethyl- 
ethyUcarhmol, (CH3) ,C (OH) . CH, . CH3. •* 

With ethylene hydrocarbons of high molecular weight, there is 
chiefly production of polymers, particularly dimers. Thus duodecene 
is changed by sulphuric acid quantitatively into viscous tetracosene 
which is stable in presence of sulphuric acid.** 

The concentration of the acid determines the nature of the re- 
action. Thus a-hexene and 7-heptene, with 85% acid yield alkyl 
sulphuric acids, while they polymerize in contact with the normal 
acid, H2SO4. 

The acid, diluted with 20% of its volume of water, changes 
isobutene, in the cold, to tributene, boiling at 177°.** 

TrimethyUethylene in contact with sulphuric acid diluted with 
half its volume of water, fiuuishes, at 0°, much diamylene, boiling 
at 164^*^ 

211. Zinc chloride can polymerize unsaturated hydrocarbons, e. g. 
trimethyl-ethylene into diamylene, triamylene, and tetra-amylerie.^^ 

Boron trifluoride transforms amylene into diamylene.^^ 

The use of catalysts under high pressures greatly favors the poly- 
merization of ethylene into unsaturated hydrocarbons at high tem- 
peratures. The products obtained with anhydrous alumina, under 
70 atmospheres above 250°, are the same as those produced by heat 
alone in the absence of the catalyst.^* 

Ethylene with anhydrous zinc chloride at 275° and 70 atmospheres, 
gives a gas containing 36% ethylene, 3% hydrogen, and 61% satu- 
rated hydrocarbons and a complex liquid of which 85% is pentane 
and hexane without any methyl-cyclobutane. The remainder consists 
of numerous hydrocarbons including unsaturated hydrocarbons boil- 
ing above 145° and naphthenes which are particularly abimdant 
aroimd 250°. 

Anhydrous aluminum chloride produces little effect with ethylene 
at 70 atmospheres and 240°, but at 280°, a gas is obtained containing 

*> Bbooks and Humphrey, /. Am. Chem. 80c., 40, 822 (1918). 

*^ WiscHNBOBADSKT, Annalen, xgo, 336 (1877). 

*(^ Bbooks and Humphrey, Loc. cU, 

•• BuTiJSROW, Berichie, 6, 661 (1873). 

*7 ScHNEiDEB, Annalen, 157, 207 (1871). 

•» Bauer, Jahresb,, 1861, 660. 

«» Landolph, Berichte, la, 1578 (1879). 

''^ Ipatdet, J. Russian Phys. Chem, Sac, 43» 1420 (1911), C. A., 6, 736. 



79 CONDENSATIONS BY ADDITIONS 214 

only Baturated hydrocarbons, and no liquid, but, instead, a rather 
abundant carbonaceous residue/^ 

212. Doubly Unsaturated Hydrocarbons. Acetylene is ad- 
sorbed more energetically than hydrogen by colloidal palladium and 
is to a great extent polymerized.^^ 

AUylene is absofbed by concentrated sulphiaric acid and is poly- 
merized into mesitylene: " 

3 CH3 . C i CH - CeH,{CH,),(l .3.5). 

This can be explained by assuming that the acid first causes the 
hydration of the allylene to acetone (308) and then dehydrates 3 
molecules of this according to a well-known reaction. 

Similarly crotonylene, or butine(2), shaken with slightly diluted 
sulphuric acid (1 part water to 3 parts acid), gives hexamethyl-ben^ 
zeneJ^ 

Valerylene, C^Hg, shaken with sidphiaric acid changes into poly- 
mers, trivalerylene and polyvaleryleneaJ'^ 

213. Divinyl, or butadiene, CH, : CH . CH : CH,, as well as its 
higher homologs, piperylene, CH, . CH : CH . CH : CH,, isoprene, 
CH, : C(CH,) . CH : CH„ and dipropylene, CH, : C(CH,) .- 
C (CH,) : CH,, polymerize spontaneously under the influence of heat 
alone giving rise to various elastic solid hydrocarbons resembling 
natural rubber and constituting the synthetic rubbers. This poly- 
merization is greatly accelerated by the presence of various catalysts. 
Thus with 5% metallic sodium or potassium, the reaction which goes 
on in the cold or with slight warming, is complete and is not hindered 
by the presence of non-polymerizable hydrocarbons.^* 

214. The polymerization of isoprene by barium peroxide or ben-' 
zoyl peroxide or potassium sulphide gives rise to the intermediate 
formation of fi-myrcene, 

CH, I CH . C I CH . CH, . CH, . C i CH,, 

CH, CH, 

a hydrocarbon boiling at 63^ at 20 mm., which, in turn, warmed with 
sodium or with barium peroxide changes quantitatively into normal 

^ Ipatibf and Rutala, Berichte, 46, 1748 (1913). 

7s Paal and HoHSNaoani, BerichU, 43, 2684 (1910). 

7* ScmiOHS, Berichte, 8, 17 (1876). 

7« Almsdinobn, J. Russian Phys, Chem, 80c., 13, 392 (1881), C, 18S1, 629. 

76 BoucBABDAT^ BuU, 8oc. Chim. (2), 33, 24 (1880). Rbboul^ Atmalen, 143, 
373 (1867). 

7* Matthbws and Stranob, English Pat., 24,790 (1910). Habbies, Annalen, 
383, 157 (1911). 



216 CATALYSIS IN ORGANIC CHEMISTRY 80 

caoutchouc; the direct polymerization furnishes only an abnormal 
caoutchouc.^'' 

215. Glacial acetic acid and especially acetanhydride acting at 
150^ have been recommended for the polymerization into caout- 
chouc/* the presence of 0.2% of sulphur or of 0.002% of sulphuric 
add in the hydrocarbon being favorable to the reaction.^* 

Trioxymethylene, at a high temperature in an autoclave, has also 
been proposed as a catalyst in this reaction.*^ 

216. Cyclic Hydrocarbons. Pinene heated twelve hours with 
formic acid changes to a hydrocarbon of double the molecular weight, 

Pinene is transformed into colophene, CsoHs,) by contact with con- 
centrated sulphuric add, boron fluoride, or phosphoric anhydride.^ 

Pinene heated to 50° with 20% of antimony chloride is changed 
into tetra-terebenthine, C^qH^^. ** Aluminum, ferric, and zinc chlo- 
rides cause the formation of analogous products.'^ 

217. Indene. Indene polymerizes on contact with sulphuric acid 
into para-indene, (CeH,),, which melts at 120** .•• 

Aldehydes 

218. The tendency to poljrmerize is very general among aldehydes 
and small traces of various materials are sufficient to cause the poly- 
merization to take place, whether the molecules thus condensed are 
joined by carbon to carbon or by means of the oxygen atoms. 

219. Aldolization. The first method of condensation is called 
aldoUzatUm; one of the aldehyde groups is preserved and the other 
is converted into a secondary alcohol group. The name comes from 
aldol, the first example to be studied. 

Acetaldehyde kept for some time in contact with a small amount 
of hydrochloric add or of zinc chloride solution condenses to give 
aJldol, or butanalol (1.3):** 

CH, .CHO + CH, . CHO — CH, . CH (OH) . CH, . CHO 

^' OsTBOMUisLBNsxn and Kobhelbv, J, Russian Phys. Chem. Soc^ 47, 1928 
(1915), C. A,, xo» 1947. OsTBOMmsLXNSKn, Ibid., 48, 1071 (1916), C. A., xx, 1768. 
7* Chsm. Fabb. Aur. Actibn, French Patent, 433,825. 
7* Badischs, French Patent, AMfilN. 
•0 Gross, French Patent, i&9fi87. 
•1 Lafont, Ann. Chim. Phys. (6), 15, 179 (1888). 

» SAiNTB-CLAiiaB-DEvn.LB, Ibid. (2), 75, 66 (1839) and (3), 96, 85 (1849). 
•s Prins, Chem. Weekbl, 13, 1264 (1916), C. A., 11, 586. 
«« RiBAN, Ann. Chim. Phys. (5), 6, 42 (1875). 
^ Kbambb and SmxER, Berichte, 33, 3278 (1890). 
•• Wubxz, Compt. rend., 74t 1361 (1873) and 76, 1165 (1873). 



81 CONDENSATIONS BY ADDITIONS 222 

The same result is obtained more readily by leaving acetaldehyde 
for 18 hours in contact with a solution of neutral potassium carbonate 
or with a fragment of solid caustic potash." Also in the presence of 
zinc turnings at 100^, acetaldehyde ^ves aldol and likewise crotonic 
aldehyde by loss of water (795) . 

220. Likewise bemaldehyde heated with an alcoholic solution of 
potassium cyanide (10% of the weight of the aldehyde), is rapidly 
transformed into bemoine, CJi^ . CH (OH) . CO . CeH,. •• The 
original aldehyde group is in this case changed to a ketone. 

Anisaldehyde, CH,0 . CeH^ . CHO, with the same reagent, gives 
anisdine, CH, . O . CeH^ . CH (OH) . CO . C^H, . O . CHj. " 

On heating an hour and a half, the same catalyst transforms 
cuminaldehyde into cumindine^ and in half an hour, furfural into 
/iir/wroine.** 

221. The aldolization of several molecules of aldehyde can be 
realized successively or sunultaneously. 

Under the influence of milk of lime, formaldehyde condenses to 
a hexose, CH, (OH) . CH (OH) . CH (OH) . CH (OH) . CO . CH,OH, 
which is racemic laevulose.^ Analogous condensations giving in- 
active arabinose and laevulose, are realized in contact with granulated 
tin,^ or with a mixture of magnesia, magnesium sulphate, and granu- 
lated lead.^^ A similar condensation can be obtained starting with 
trioxy methylene, (HCOH),. •' 

222. Second Method. The second method in which aldehydes 
poljrmerize suppresses the aldehyde fimction, producing bodies called 
paraldehydes and metaldehydes, the vaporization of which tends to 
reproduce the original aldehyde. 

Acetaldehyde in contact with small quantities of sulphur dioxide, 
anhydrous zinc chloride, hydrogen chloride, or carbonyl chloride soon 
warms up and is converts into paraldehyde, boiling at 124^. The 
same result is obtained by warming it with ethyl iodide or by leaving 
a solution of cyanogen in acetaldehyde to stand for several days.** 

*7 MicHABL and Kopp, Am, Chem, Jour,, 5, 190 (1883). 

•* W5HUEB and Limia, Annalen, 3, 276 (1832). Zinin, Ibid,, 34, 185 (1840). 
BsBUBs and Zincks, Ibid,, Z98, 151 (1879). 

M Rossn*, Ibid,, 251, 33 (1869). 

•<» B5SLBB, Berichte, 24, 324 (1881). 

*^ E. FiscRBB, Annalen, azz, 218 (1882). 

M LoBw, Berichte, aa, 475 (1889). E. Fischsb and Passmobi, Ibid,, 22, 359 
(1889). 

M LoBW, J, prakt, Chem, (2), 34, 51 (1886). 

•♦ LoBW, Loc, cii. 

*' S bkzwix and Gdello, Compt. rend,, Z38, 150 (1904). 

** Loams, Annalen, SupL Band, 1, 114 (1861). 



223 CATALYSIS IN ORGANIC CHEMISTRY 82 

A few bubbles of hydrogen chloride or sulphur dioxide passed into 
acetaldehyde cooled below 0^, convert it into metaldehyde, a sublim- 
able solid.*^ By adding one drop of concentrated aulphv/ric acid to 
100 cc. acetaldehyde, paraldehyde is obtained. 

223. Likewise by passing a few bubbles of hydrogen chloride into 
propionic aldehyde cooled below 0®, crystals of metapropanal (melt- 
ing at 180^) are obtained along with parapropanal, a liquid boiling 
at 169^. By a current of hydrogen chloride at — ^20^, metapropanal 
is formed.*' 

When a current of dry hydrogen chloride is passed into butanal at 
— ^20®, heat is evolved and, on stopping the gas, crystals of meta- 
butanal (melting at 173°) separate out along with oily parabutanal. 

Under the same conditions, cenanthal (heptaldehyde) gives para^ 
heptaldehyde (melting at 20°) and metaheptaldehyde (melting at 
140°). •• 

224. Isobutyric aldehyde, with a concentrated solution of sodium 
acetate at 160°, is changed into the dialdehyde boiling at 136°.^^ 
With a little chlorine, bromine, iodine, hydrochloric acid, phosphorus 
pentachloride or zinc chloride, meta-isobutanal, melting at 59°,^®^ is 
produced. 

With alcoholic potash it gives in succession, tri-iaobvtanal 
(b.l54°), tetra-iaobutanal (b.l90°), penta-isobutanal (b.223°), hexa- 
isobutanal (b.250°), and finally oily hepta-isobutanal}^* 

Chloral behaves similarly in contact with various substances, 
forming solid insoluble metachloral with sulphur dioxide. Trimethyl 
amine produces the same effect rapidly ;^^' fuming sulphuric add 
causes the same polymerization,^®^ while pyridine gives metachloral 
in a gelatinous form.^®'' 

226. Third Method. Aromatic aldehydes, e. g. benzaldehyde, 
when warmed with alkali, undergo a special change, yielding the al- 
cohol and acid at the same time: 

2CeH5.CHO + KOH - CeHtCOsK + CeHjCHsOH. 

•^ KsKviA and Zincke, Ibid., x6a, 125 (1872). 

»» Orndorf, Amer. Chem. J., la, 353 (1890). 

** Fbanxs and Wozelka, Monatah., 33, 349 (1912). 
i«o F0S8IK, Ibid., a, 622 (1881). 

^0^ Babbaglu, Berichte, 5, 1052 (1872) and 6, 1064 (1873). Dbmtschinko, 
Ibid., 6, 1176 (1873). 

10* Perkin, J. Chem. Soc, 43, 91 (1883). 

i«» Mbtbr and Dulk, Annalen, 171, 76 (1874). 

10* B5E8BDBN, Rec. Trav. Chim. Pays-BoB, ag, 104 (1910). 

^«» BfiasBKEN and Schimmd., Ibid., 32, 112 (1913). 



83 CONDENSATIONS BY ADDITIONS 228 

Formaldehyde gives the same reaction to some extent with dilute 
caiistic soda.^^ On the contrary, acetaldehyde, with caustic soda or 
potash, polymerizes into a complex resin. 

226. iBohutyric aldehyde with baryta water reacts somewhat like 
aromatic aldehydes, yielding isobutyl isobutyrate: 

(CH,),CH . CHO + CHO • CH(CH,), - (CH,)2CH • CO • OCH, • CH(CH,), • 

When the solution is warmed, the ester is saponified into isobutyl aU 
cohol and iaobutyric acid}^'' 

227. This reaction takes place with all aliphatic aldehydea in 
which the carbon atom next to the aldehyde group carries no 
hydrogen. 

It is sometimes caused by the presence of ethyl magnemtm iodide. 
With 2^-dimethyUpropanolal' the hydroxypivalic ester of 2,2-dt- 
methyl'propandiol is obtained: ^®* 

CH,v/CH,OH OHC\V/CH, 

CH^ \CHO HOHjC/ \CH, 

CHsvyCHiOH yCHjOH 

CHa/ XcHjOCO/ ^^(CH,), 

228. The same reaction can be brought about with the lower 
aliphatic aldehydes by the use of aluminum ethylate, A1(0C2Hb)s 
(299). Thus formaldehyde is condensed into methyl formate, ace^ 
taldehyde into ethyl acetate, propiomc aldehyde into propyl propio^ 
nate, even chloral into trichlorethyl trichloracetate}^^ 

In the case of acetaldehyde this reaction goes quantitatively in 
24 hours if 4% of ethyl aluminate be used and the mixture kept below 
15°. The ethylate can be used in solution in ethyl acetate, xylene,**® 
or solvent naphtha?^^ 

The reaction is carried out in this way : To 135 parts of acetalde- 
hyde, 6 parts of aluminum ethylate containing 10% alimiiniun chlo- 
ride are added little by little and the mixture let stand for ten hours. 
The yield is 123 parts ethyl acetate.*" 

io« H. & A. EuLBB, Berichte, 38» 2556 (1906). 
107 Fbanxs, MonaUh. Chem^ ax, 1122 (1900). 
10* Fbankb and Kohn, Ibid., as, 865 (1904). 

109 TiscHXNKO, J. Russian Phys. Chetn. Soc, 33, 260 (1901). 

110 EoNSORTiUM F. Elbktroch. Ind., EnffUak pat, 26^25 and 26326 of 1913. 
/. 8. C. L, 33, 666 (1914). Gernum pat., 277,188 (1913); Imbat, Engliah pat., 
1,288 of 1916, J. 8. C. I., 35» 141 (1916). 

111 Oerman pat., 308,043 (1918), Chem. Centr., 29x8 (2), 613. 

112 KoNSOBTnTM F. EusKTBOCH. Ind., French patent, 465,965. J. 80c. Chem. 
^^< 33> 666 (1914). 



^d CATALYSIS IN ORGANIC; CHEMISTRY 84 

Ketones 

229. The ketones rarely polymerize but usually condense with 
the loss of water. 

However, aldolization of acetone takes place in the cold with a 
concentrated solution of caustic soda.^^* Thus: 

CH,.COCH, + COC -CHt.COCH,.C(OH)( 

NCH, \CHi 

When the product is heated with the same alkali, the reaction is 
reversed. 

Nitriles and Amides 

230. Hydrocyanic acid, or formic nitrile, HON, kept with caustic 
potash or an alkaline carbonate, desposits crystals of the empirical 
formula (CNH), which are soluble in ether and appear to be the 
nitrile of amino-malonic acid, CN . CH (NH,) . CN, along with brown 
amorphous material.^^^ The same substance is obtained when a small 
fragment of solid potassium cyanide is added to a water solution of 
hydrocyanic acid.*^' 

231. Propionic nitrile, CH, . CH, . ON, dissolved in its own weight 
of anhydrous ether in contact with 20% metallic sodium is converted 
into dipropionic nitrile, melting at 47^.^^* Under the same conditions, 
acetonitrile, CH, . CN, is converted into diacetonitrUe, CH, . C (NH) .- 
CH,.CN, melting at 52^"^ 

232. When, the same nitriles, pure and without the ether, are 
heated with metallic sodium or potassium (1 of metal to 9 of nitrile), 
they are polymerized into their trimers, acetonitrile into cyanethvne, 
(C,NH.).."« 

Bemonitrile polymerizes on contact with sulphuric acid into 
cyaphenine: *" 

yCr— CeH» 
fN^ \n 

CeHi — Cv yC — CeHs 

lis Kqbuchbn, Z. phys, Chem,, 33, 129 (1900). 

"♦ WippiBMANN, Berichte, 7, 767 (1874). 

^iB Lbscoeub and Rigaitt, Compt. rend^ 89, 310; BuU. Sac, Ckim, (2), 34, 
473 (1880). 

ii< VON Mktbr, J. prakU Chem. (2), 38, 337 (1888). 

1" HowzwABT, Ibid, (2), 39, 230 (1889). 

^^* Frankland and Kolbb, Anndlen, 65, 209 (1848). Batb, Berichte, a, 
319 (1869) and 4, 176 (1871). von MEmt, J. prakL Chem. (2), 97, 153 (1883). 

^^* HoniANN, BeriehU, z, 198 (1868). 



85 CONDENSATIONS BY ADDITIONS 286 

233. Cyanamide, either in the cold in contact with concentrated 
caustic 8oda or potash, or in a hot solution to which is added a little 
ammonia, is transformed into dicyanamide}*^ 

§3. DEPOLYMERIZATIONS 

234. Depolymerizations are far more rare than pol3rmerization8, 
since the polymers usually correspond to a much more stable molec- 
ular state. In exceptional cases, polymers can be decomposed into 
the sunple molecules by the action of heat and this return is greatly 
facilitated by the very catalysts that cause the polymerization. 

This is the case with paraldehydes and metaldehydes. The cat- 
alysts which at low temperature polymerize the aldehydes into their 
trimers break these up at high temperatures to regenerate the alde- 
hydes. A trace of concentrated sidphuric acid, hydrochloric acid, 
calcium or zinc chloride or the like is suflScient to change hot par- 
aldehydes into the monomolecular aldehydes.^*^ Likewise metolde^ 
hydes are transformed into the aldehydes by heating with dilute sul- 
phuric acid.*" 

Certain aldols can be decomposed, by warming with a trace of 
potassium carbonate, regenerating the two molecules of the original 
aldehyde. But with benzoine and analogous compoimds this decom- 
position does not take place simply. 

235. The transformation of pinene and especially of dipentene, 
^10^169 ^^ isoprene, C^B.g, which is realized by the action of an in- 
candesc^t platinum spiral,*" appears to be due to the catalytic action 
of the metal, for this reaction can be caused by passing the vapors of 
the terpene over pumice impregnated with platinum black in an iron 
tube at a very low red.*** 

§4. CONDENSATIONS BETWEEN DISSIMILAR 

MOLECULES 

Aldehydes and Ketones 

236. Aldehydes and ketones can add molecules of other kinds, 
the reactions being comparable to aldolizations and aided by catalysts 
of the same nature. 

^s<^ Haao, Atmalen, zaa, 22 (1882). Baumann, Berichie, 6, 1373 (1873). 
Gbubb and Kb^cbr. Zeit, phys, Chem,, 86, 05 (1914). 

^<i Fbanxs and Kohn, MonaUh. Chem., Z9» 354 (1808). 

"• BtJRSTYN, Ibid., as. 737 (1902). 

^*> Habbus and GiOttlob, Annalen, 383, 228 (1911). SiAUDiNami and Eubvb, 
BeriehU, 44, 2212 (1911). 

^*^ ScHOBOB and Satbb, /. Ind, Eng. Chem., 7» 024 (1915). 



237 CATALYSIS IN ORGANIC CHEMISTRY 86 

This reaction is general between aldehydes and nitroparaffinea and 
gives nitroalcohols. The presence of an alkali, or better an alkali 
carbonate, is sufficient to cause the reaction. 

By adding a small fragment of potassium bicarbonate to a mix- 
ture of equal molecules of nitromethane and acetaldehyde, with an 
equal volmne of water, lHfUtropropanol(2) is obtained: ^^^ 

CHsCOH + CHJJOi - CH,.CH(0H)CHJI02- 

Likewise nitroethane condenses with formaldehyde in the pres^ice 
of a little neutral potassium carbonate to give 2-^tropropyl alcohol, 
CH, . CH(NO,) . CH,OH.^«« 

Several aldehyde molecules may take part in the reaction. Nitro- 
propane and formaldehyde with a little potassium carbonate give 
2-mtrO'fnethanol(2)-^utanol{l) : "' 

CH,CH2CH2NOi + 2HCHO - CH,CH2C(N02)(CH20H)r 

A mixture of formaldehyde (commercial formaldehyde solution) 
and nitro-methane reacts violently on the addition of a fragment of 
potassiiun bicarbonate to give 2-nitro'methylol{2)propanediol(lfi), 
a nitro-triprimary alcohol melting at 158^.^^' 

3HCH0 + CHJ^Ot - C(N02)(CH20H),. 

237. The mixture of glyceric aldehyde and dihydroxyacetone 
which is produced by the air-oxidation of glycerine in the presence of 
finely divided platinum (92), condenses into i-laewlose in contact 
with a water solution of caustic soda: **• 

CH2OH • CHOH . OHO + CH2OH • CO • CH2OH - 

CHjOH . CHOH • CHOH • CHOH • CO • CH2OH • 

238. Acetone reacts with chloroform in the presence of solid caus^ 
tic potash to give acetone-chloroform or trichlor-tertiary-butyl 
alcohol: 

(CH,)2C0 + HCCU - (CH,)2C(0H) ecu- 

To a mixture of 500 parts acetone and 100 parts chloroform, 300 
parts of pulverized caustic potash are added very slowly and the mix- 
ture left for 36 hours."^ 

239. Anhydrous aluminum chloride can sometimes cause the same 

"s Hbnbt, BuU. 80c. Chim. (3), 13, 003 (1895). 
"« HsNBT, Ibid., IS, 1223 (1896). 
isr Paxtwbls, Chem. CerUbl, 1898 (1), 193. 
zM Hbnbt, Compt, rend., xax, 210 (1896). 

zM E. FiscHBR and Taisl, Berichte, aa, 106 (1882). Wohl and Nkubbui, 
lUd^ 33> 3096 (1900). 

^*o WmumBon and Osniesbb, J. prakt, Chem, (2), 37, 361 (1888). 



87 CONDENSATIONS BY ADDITIONS 224 

sort of reactions Thus chloral gives an addition compound with 
naphthalene, CioH,.CH(OH) .CCV^ 

240. Acetylation of Aldehydes. The addition of the anhydrides 
of monobasic organic acids to aldehydes yields esters of the ethylidene 
glycols corresponding to the aldehydes. This reaction is catalyzed 
by the presence of various metal salts, copper sulphate, zinc chloride, 
ferric chloride, and stannic chloride and even by sulphuric acid. Thus 
benzaldehyde and acetanhydride give benzyUdene acetate quantita- 
tively in the presence of copper sulphate: 

CcHftCHO + (CHsCOaO - CeHsCHCOCOCH,),- 

In the presence of stannic chloride, vanilline gives a quantitative 
yield of the triacetate, the phenol group being simultaneously 
acetylated.*'* 

Hydrocarbons 

241. Unsaturated hydrocarbons, ethylerUc or acetylenic, may add 
themselves to hydrocarbons in the presence of aliuninum chloride.^*' 
By passing acetylene into benzene containing aliuninum chloride, 
symmetrical dipheruyUethane is obtained: ^'^ 

CeHe + CH : CH + C9H3 — C«H5 • CHs • CHj • CeHs 

and also a certain amount of styrene formed by the addition of only 
one molecule of benzene: 

C»He + CH i CH - CJIsCH: CH,. 

By passing ethylene into a warm mixture of diphenyl and alumi- 
num chloride, ethyUdiphenyl is obtained: 

CeHs'CftHft H" CHj: CH2 ■ CeHs'CeHi'CHs'CHs 

along with some of the diethyl derivative.^'" 

242. In an analogous way anhydrous aluminum chloride causes 
the addition of carbon tetrachloride or of chloroform to ethylenic 
chlorine derivatives. 

Thus trichlor ethylene, CCI2 : CHCl, gjves, 'with carbon tetra- 

isi Fbankfobisb and Dandels, J. Amer, Chem. Soc, 37, 2660 (1915). 

^>2 Knqbvbnagbl, Annalen, 40a, 111 (1913). 

iss xhis may be considelred as a case of the Friedel and Crafts reaction. 
A tnuse of water is always present and reacts with the aluminum chloride to 
give hydrochloric acid which adds to the hydrocarbon to form an alkyl chloride 
which then reacts in the usual way liberating hydrochloric acid which repeats 
the reaction. — £. E. R. 

184 Yjjon and VneNNS, BuU. Soc. Chim. (2), 47» 919 (1887). 

^s« Adam, BvU. Soc. Chim. (2), 47, 689 (1887) and Ann. Chim. Phys. (6), 
15. 262 (1888). 



24S CATALYSIS IN ORGANIC CHEMISTRY 88 

chloride, heptachlorpropane, CCl, . CHOI . CClg, boiling at 249^, and 
with chloroform, hexachlorpropane, CCl, . CHCl . CHCl,, boiling at 
216^ 

Likewise dichlor ethylene, CHOI : CHOI, and chloroform give 
symmetrical pentachlorpropane, CHOI, . CHCl . CHCl,, boiling at 
198^.^'* See Chapter XX for the reverse reactions caused by 
almninum chloride. 

243. Stannic chloride causes an analogous addition of ethylemc 
or cyclohexenic chlorides to acid chlorides to torm a-^chlorketones. 
Aluminum chloride also can be used as catalyst in the reaction but is 
not so good."^ 

»« Pbinb, J. prakt. Chem. (2), 89, 414 (1914). 
^>^ DAazKNB, Compt. rend^ 150, 707 (1010). 



CHAPTER V 
OXIDATIONS 

I. Direct Oxidations by Gaseous Oxygen 

244. The action of oxygen on various substances, or oxidations, 
can be divided into three groups: 

1. Oxidations which take place spontaneously as soon as the 
oxidisable material and oxygen are brought together under the proper 
conditions of temperature and pressure.^ 

2. Oxidations which are brought about by the simultaneous oxida- 
tion of certain substances called auto-oxidisera. 

3. Oxidations effected by substances which are apparently un« 
changed and which are called oxidation catalysts. 

At first sight only the latter seem to belong in the present treatise. 
But even in the first group, catalytic phenomena are of more or less 
importance. We have already mentioned (73) the influence of 
moisture on reactions. Practically, the amounts of water vapor con- 
tained in the air or in the oxyg^i, even when they are dried by the 
usual means, are sufficient to facilitate oxidations of the first class. 

The case of induced oxidations, that is as a consequence of sunul- 
taneous oxidations, has been examined in Chapter III (150), and we 
have shown how we can sometimes pass from the mechanism of such 
reactions to catalytic oxidations which should be specially examined. 

245. Platinum. The direct formation of a sort of unstable oxide 
on the surface of the platinum (154) permits us to explain the im- 
portant rdle of this metal in many oxidations. Its activity should 
be proportional to its surface and it can be shown that the surface 
is immeasurably larger for platinum sponge and especially for the 
black than it is for the same amount of metal in foil or wire. 

246. The use of platinum black enables us to effect many oxida- 
tions. Ethyl alcohol poured on platinum black is vigorously oxidised 
to acetaldehyde and acetic acid; the black is sometimes made incan- 
descent and the alcohol may take fire. 

^ In cases of this kind it is practically impossible to eliminate the cat&iytic 
effect of the interior surfaces of the walls of the containing vessel and hence it 
is sometimes difficult to distinguish between reactions of this kind and those of 
Class 3.— H. D. Gibbs. 

89 



247 CATALYSIS IN ORGANIC CHEMISTRY 90 

Formic and oxalic acids are burned to water and carbon dioxide.' 
Alcohols are usually oxidised to aldehydes and even to acids. 

Cinnamic aldehyde can be obtained thus from the corresponding 

alcohol.' 

By oxidising glycerine by air in the presence of platiniun black, 

the isomers, glyceric aldehyde and dihydroxy acetone, are obtained: * 

CHjOHCHOHCHjOH + O - H,0 + CH2OH • CHOH • CHO 
CHjOH • CHOH • CHjOH + O - ao + CH,OH • CO • CH,OH • 

However, platinum black has no effect on a mixture of carbon 
monoxide and oxygen.' 

247. The results given by the black are irregular because its action 
is too violent, particularly at the beginning of the reaction. 

By substituting for it, platinized asbestos where the active ma- 
terial is diluted by a large proportion of inert material, regular oxida- 
tion of vapors mixed with suitable amounts of oxygen or of air, is 
obtained. The manufacture of sulphur trioxide is only an application 
of this on the large scale. 

248. Colloidal platinum (67) has intense oxidising power, greater 
than that of the black. It gives 50% carbon dioxide with a mixture 
of carbon monoxide and half its volume of oxygen.' 

249. Platinum in very fine wire or very thin foil is employed 
industrially in the oxidation of ammonia gas by the oxygen of the 
air. The gaseous mixture, previously heated to about 300^, is passed 
over the metal which is thereby maintained in incandescence.' Con- 
tact with the metal for one-five-himdredth of a second is sufficient 
to obtain a good yield of nitrous vapors which are easily transformed 
into nitric acid. 

It furnishes also an excellent method for the regular oxidation of 
alcohols and of other sufficiently volatile organic substances.^ Trillat 
has described a method of operating which makes it easy to attain 
this end by the aid of a platinum wire which is heated by a current 
that can be regulated at will for any desired temperature ' and over 
which a current of air passes laden with the vapors of the substance 
to be oxidised. 

2 MuLDBB, Bee, Trav. Chim. Paya-Baa, a, 44 (1883). 

* Stbickbb, Annalen, 93, 370 (1855). 

« GRiMAini:, Bull. 80c, Chim. (2), 45, 481 (1886). 
« Paal, BerichU, 49 548 (1916). 

* The points that are used in p3a*ography for burning designs on wood 
contain leaves of platinum foil which are heated by the catalytic combustion 
of the mixture of air and combustible vapors forced over them. — E. £. R. 

^ Better cataljrsts than platinum are known for the oxidation of many 
alcohols. See note to 254 infra. — H. D. Gmss. 
s Tbolat, BvU. 80c. Chim. (3), 27, 797 (1902). 



91 OXIDATIONS 261 

Under these conditions methyl alcohol is oxidised below 200^ 
chiefly to formaldehyde with some methylal and water but no acid. 
The acid appears when the spiral reaches a dull red, at the same time 
that the formaldehyde and methylal increase. At a cherry red these 
decrease and the proportion of carbon dioxide increases with increase 
of incandescence. 

The presence of water in the methyl alcohol favors the oxidation 
which goes best when 20% of water is present. 

Ethyl alcohol is oxidised as low as 225^ and readily at a dull red 
with a yield of 16.8% of acetaldehyde and 2.3% acetal. The results 
are less and less favorable as the molecular weight of the alcohol 
increases. 

With propyl alcohol the yield of aldehyde is about the same as 
with ethyl, but is 12% for normal butyl alcohol and 6% for i8oby;tyl. 
Isopropyl alcohol gives 16% acetone. Tertiary butyl alcohol breaks 
up, on oxidation, into formaldehyde, acetone and water. 

Allyl alcohol gives 5.8% acroleme, some acrylic acid, formaldehyde 
and glyoxal. 

Glycol oxidises at 90^, raising the spiral to incandescence and 
yielding formaldehyde, glycolic aldehyde and glyoxal.^ Glycerine 
gives principally fonnaldehyde and acroleme. 

Aromatic alcohols likewise produce some of the corresponding 
aldehyde. Benzyl alcohol has furnished 4% bemaldehyde and 
cuminyl alcohol, 5.7% cmninic aldehyde. 

Cmnamic alcohol gives some cinnamic aldehyde at a dull red and 
cinnamic acid and benzaldehyde at higher temperatures. 

Uoeugenol oxidises at a dull red to give 2.9% vanilline mixed with 
the unchanged substance.^^ 

250. The use of porous porcelain impregnated with platinum is 
advantageous for securing the complete oxidation of organic com- 
pounds in combustion analysis.^^ 

251. Metals of the Platinum Group. The various metals of this 
family may be used as sponge or better as black for the same pur- 
poses. 

Palladium black gives good results.^* 

OBmium, a more moderate catalyst, sometimes has advantages. 
In the oxidation of cyclohexene, it gives some cyclohexenol accom- 

TftnxAT, Bvll. Sac, Chim, (3), 99, 35 (1903). 
10 TiOLLAT, BvU. 80c, Chim, (3), 99. 35 (1003). 

1^ Casbasoo and Bbixoni, /. Pharm. and Chim. (6), 27, 469; Chem, Centbl^ 
Z908 (2), 95. 

" Whlanb, Berichie, 46, 3327 (1913). 



262 CATALYSIS IN ORGANIC CHEMISTRY 92 

panied by adipic acid and other products. The other metals of the 
platinum family are not suitable for these reactions. 

Tellurium may be used, but it is less active than osmiiun.^' 

Colloidal irridium can catalyze the oxidation of carbon monojdde 
as does colloidal platinum, but colloidal osmium is less efficient.^* 

252. Gold and Silver. Gold and silver can be substituted for 
platinimi in the preparation of jormaldehyde. Silvered asbestos ob- 
tained by the reduction of the nitrate by formic acid and asbestos 
gilded by the reduction of the chloride are more active than platinized 
asbestos (245).^' 

263. Copper. In the oxidation of methyl alcohol by the method 
of Trillat (248), the platinum spiral can be replaced by a roll of 
copper gauze heated to a dull red. 

The results obtained are entirely similar. In operating thus witii 
a current of 2.3 to 2.7 liters of air per minute, carrying 0.5 to 0.8 g. 
methyl alcohol, copper gauze gives a yield of 48.5% formaldehyde 
at 330^. There is at the same time production of carbon monoxide, 
carbon dioxide and water vapor.^* 

The direct oxidation of methane by air in contact with copper or 
silver is a practicable method for preparing formaldehyde. A mix- 
ture of one volume of moist air with three volumes of methane ia 
passed over either of these metals or over a mixture of the two. The 
formaldehyde that is produced is taken out by contact with water 
and the residual gases are passed again over the catalyst.^^ 

254. Fokin, operating under identical conditions with air saturated 
with methyl alcohol vapor passed over various catalysts, has obtained 
the following yields of formaldehyde (figured on the methyl alcohol 
used) : *• 

Gilded asbestos 71% 

Silvered asbestos 64-66 

Coppered asbestos 43-47 

Platinized asbestos ' b2 

Reduced cobalt 2.8 

Manganese in powder 2 

Aluminum turnings 1.5 

Reduced nickel 1.08 

^* Wn^LSTATTBR and Sonnsnfbld, Berichte, 46, 2952 (1913). 

i« Paal, Berichte, 49> 548 (1916). 

^« Fokin, J. Russian Phys. Chetn. Sac, 45, 286 (1913) ; C. A,, 7, 2227. 

^« OBLorr, J. Russian Phys. Chetn. 80c., 39, 855 and 1023 (1907) ; C. A., a» 
263 and 1692. 

^7 Vebein f. Chkm. Inb., Oerman patent, 286,731, /. 80c. Chem. Ind., 35, 
73 (1916). 

^« FoKZK, J. Russian Phys. Chem. 80c., 45, 286 (1913) ; C. A., 7, 22IN. 



93 OXIDATIONS SW 

A maximiim yield of 84% was obtained by a mixture of silver and 
copper. The silvered or gilded asbestos requires an initial tempera- 
ture of only 200-250° and the heat evolved is sufficient to maintain 
it at a suitable temperature. 

Copper used alone requires continual heating, but this can be 
avoided by placing ahead of the copper gauze some fragments of 
pumice impregnated with platinum or palladium the incandescence of 
which heats the gas sufficiently.^* 

The presence of lead in the copper is imfavorable. 

Ethyl, propyl, isobutyl and isoamyl alcohols may be oxidised 
under like conditions.*^ Ether is oxidised to formaldehyde and acet- 
aldehyde.*^ Various hydrocarbons have been submitted to regular 
oxidation by the same process but the products have not been fully 
studied.** 

255. As acetaldehyde can be prepared from acetylene (309), its 
direct oxidation to acetic acid is an interesting industrial problem. 

It appears to be realized by the use of platinum; the aldehyde 
vapors carried by air or oxygen over platinized asbestos kept at 130- 
40° are regularly transformed into acetic acid.*' 

256. The same metals may be used as catalysts for the direct 
oxidation of ammonia or amines. 

Moist ammonia yields ammonium nitrite with a little nitrate and 
very little free nitrogen. 

Moist methyl amine gives formaldehyde along with ammoniiun 
nitrite and nitrate, while ethyl amine gives some acetaldehyde. 

Dimethylaniline produces formaldehyde and a complex aromatic 
amine.*^ Aniline, toluidine and pyridine are oxidised with the forma- 
tion of complex oily products.*' 

^* The oxidation of isopropyl alcohol has been extensively investigated by 
R. R. Williams and H. D. Gibbs in connection with the utilization of the waste 
unsaturated gases obtained in large quantities from the petroleum cracking 
stills. It was found that the best cataljrst was brass (zinc and copper). The 
isopropyl alcohol is mixed with air and passed through brass gauze at about 
200*. With a catalytic chamber of a proper volume in relation to the radiation 
surface, the reaction is continuous and requires no external heat. The yield of 
acetone is over 00% of the theory. That the reaction is essentially a dehydro- 
genation is shown by passing the isopropyl alcohol over the catalyst without 
the oxygen of the atmosphere, acetone is formed but the necessary heat must 
be supplied externally. This work was done for the U. S. Government during 
the war but the report has not yet been published. — H. D. Gibbs. 

»o Orloff, Ibid., 40, 203 (1908) ; C. A., a, 3346. 

»i Orlofp, Ibid., p. 799; C. A,, 3, 1147. 

" Orloft, Ibid., p. 652. 

*• Drbtfus, French patent, 487,412 (1918). 

** Trillat, Bidl. 80c. Chim. (3), ag, 873 (1903). 

*• OBLOfv, /. Btusian Phys. Chem. 80c., 40* 669 (1008). 



II 



267 CATALYSIS IN ORGANIC CHEMISTRY 94 ■ 

257. Carbon. The less combustible forms of carbon may serve 
as oxidation catalysts. 

Coke at 200"^ aids in transforming toluene into benzoic acid.'* '^ 
Coal and lignite after being heated in the air to 300^ are good 
oxidation catalysts between 150 and 300^ ; the action, being partly due 
to the oxide of iron which they contain, is increased by the addition 
of ferric oxide. They can be used in the oxidation of ethyl alcohol 
to acetaldehyde and acetic acid, and of toluene into benzaldehyde 
and benzoic acid. Anthracene gives anthraquinone and borneol forms 
camphor and camphoric acid.** 

258. Metallic Oxides. A large number of metallic oxides act as 
oxidation catalysts and for the most of them this property can be 
readily explained by the fact that they are readily reduced to the 
metals or to lower oxides by the substances to be oxidised and are 
readily reoxidised directly by oxygen. This is the case with the oxides 
of copper, nickel and cobalt. When alcohol vapors alone are passed 
over copper oxide moderately heated, aldehyde is formed and the 
oxide is reduced, but if the air is mixed with the alcohol vapors the 
copper is immediately reoxidised and can recommence the oxidation 
of the alcohol. A like explanation fits the case of ferric oxide, which 
can be reduced to a lower oxide which is reoxidised by the air. It is 
more difSicult to perceive the mechanism in the case of oxides which 
can not be reduced to suboxides e. g, chromium sesquioxide which is, 
nevertheless, an excellent oxidation catalyst.** 

The catalytic activity of iron sesquioxide, such as is obtained by 
roasting pyrites, is utilized industrially in the manufacture of sul- 
phuric acid by the contact process. 

259. The use of metallic oxides as catalysts in the oxidation of 
organic compoimds has until recent years been limited to copper oxide 

'* Dbnnstbdt and Hasslbb, Oerman patent, 203|84S, Chem. CentrhL, 1908, 
(2), 1760. 

27 During the war various forms of carbon were extensively studied as 
adsorbents for gases and as catalysts for certain reactions. Very active forms 
of diarcoal were developed by high heat treatments. These charcoals were 
found to be excellent clarifjring agents for solutions, and some forms catalyzed 
certain reactions to a high degree. The reaction between chlorine and water 
was found to be quite rapid at low temperatures, even so low as 0*", and at 
100' it is very vigorous. The reaction is 2 CI, + 2HjO — ► 4 HCi + O^. This 
would constitute a reversal of the Deacon process were it not for the fact that 
the oxygen does not appear as such but unites with the carbon gradually con- 
suming the catalyst. See: The Production of Hydrochloric Acid from Chlorine 
and Water. Gibbs, /. Ind. and Eng, Chem., za, 538 (1920). — H. D. Gibbs. 

«8 WooQ, CompL rend., 145, 124 (1907) ; C. A., 1, 2690. 

<* Sabatub and Mailhb, Compt. rend., Z4a» 1394 (1906); C, 1906, (2), 402. 



95 OXIDATIONS 

which is the real agent when copper is used, as has been said above. 
Sabatier and Mailhe have shown that the oxides of copper, nickel, 
and cobalt, as well as those of chromium, manganese, uranium, etc., 
have catalytic properties entirely comparable to those of finely 
divided platinum. When these oxides are heated to 200^ in a mix- 
ture of oxygen with the vapors of aliphatic hydrocarbons (methane, 
pentane, hexane, and heptane), they become incandescent and main- 
tain themselves so, giving mainly water and carbon dioxide, but also 
a certain amoimt of aldehyde and acid.'* 

Almost simultaneously with the above work, Matignon and 
Trannoy have shown the possibility of realizing a lamp without flame 
by the aid of asbestos fibers impregnated with the oxides of iron, 
nickel, chromium, copper, manganese, cerium, and silver suspended 
in a mixture of air and ether vapor.'^ 

The use of ferric oxide between 175 and 300^ permits the regular 
oxidation of toluene to benzaldehyde; the most favorable tempera- 
ture is 280** and the yield of aldehyde may reach 20%. Above 280*^ 
the oxide becomes incandescent and there is partial charring of the 
products. 

Employed in the same way, nickel oxide gives benzaldehyde above 
150^, while at 270° incandescence begins to manifest itself. 

With copper oxide (oxidised turnings), the reaction takes place 
between 180 and 260°." " 

•0 Matignon and Trannoy, CompL rend., Z4a» 1210 (1906); C, Z906 (2), 
202. 

•1 Wooo, CompL rend., 145, 124 (1907), C. A., x, 2690. 

** The catalytic 03ddation of carbon monoxide at low temperatures may be 
brought about by certain metals such as platinum and palladium but the time 
of contact necessary for complete oxidation is quite great. Mixtures of certain 
metallic oxides are much more effective and may bring about the catalytic oxida- 
tion of carbon monoxide at room temperatures with a surprisingly short time 
of contact. These mixed-oxide catalysts require careful preiparation in order 
that they may fimction under these conditions. Fineness of subdivision and 
intimacy of admixture of the ingredients are among the most essential condi- 
tions. The most important of this class of catalysts for the oxidation of carbon 
monoxide contains, as its essential constituent, manganese dioxide made by the 
method of Fr6my ((Ik>mpt. rend., 8a, 1213 (1876). Copper oxide or silver oxide, 
when properly incorporated with this manganese dioxide, g^ves an excellent 
catalyst which is capable of effecting the catalytic oxidation with great rapidity 
even at temperatures somewhat below 0"* C. 

To prepare the catalyst, the Fr^y oxide is washed free of sulphates and 
filtered on a Biichner funnel. This paste, usually containing about 60% of water, 
is analysed for moisture by drying to constant wedght at 130* in oxygen. A 
weighed amount of this paste is mixed with a large volume of cold water, care 
being taken to secure a uniform suspension. To this suspension is added such 



260 CATALYSIS IN ORGANIC CHEMISTRY 96 

260. Vanadium pentoxide is also a very active oxidation catalyst 
and can transform the vapors of ethyl alcohol mixed with air into 
acetaldehyde and acetic acid.'' Acetaldehyde can also be changed 
to acetic acid; this oxidation is readily realized by passing a current 
of air through a solution of the aldehyde in glacial acetic acid con- 
taining oxides of vanadium,'^ uranium '' and iron.'^ 

261. Cerium oxide also can be employed for transforming ace- 
taldehyde into acetic acid (256). The aldehyde mixed with 1% 
cerium oxide is submitted to the action of oxygen at two atmospheres 
or of air at higher pressures. The oxidation evolves heat and gives 
a yield of 95%." 

an amount of a solution of copper or silver nitrate, 9s the case may be, as will 
give a mixture of 75% of manganese dio3dde to 25% of the other oxide and, 
with continual vigorous stirring, a solution of sodium carbonate is run in till 
precipitation is just complete. The precipitate is filtered, carefully washed, and 
thoroughly dried at about 130". In order to produce a harder and less friable 
product, it is well to compress the material in a filter press before drying. Silver 
oxide may be precipitated by caustic soda, but with copper, sodium carbonate 
must be used, the copper caibonate passing into the oxide during the drying. 
Both silver and copper oxides may be used in the catalyst. Certain other oxides, 
such as iron oxide, may be tolerated in limited amounts and appear to act only 
as diluents. When properly prepared, these catalysts will bring about the com- 
plete oxidation of carbon monoxide provided a sufficient amount of oxygen is 
present in the mixture. Moisture is rapidly absorbed by the catalyst, diminish* 
ixig its activity, hence the gas mixture must be relatively dry for the oxidation 
to be catalytic. — J. C. W. Fhazeb. 

"' Naumann, Mobses, and Lindbnbaum, /. prakt. Chem. (2), 75, 146 (1907). 

** Vanadium pentoxide is an excellent catalyst for the oxidation of toluene 
to benzaldehyde, anthracene to anthraquinone, naphthalene to phthalic anhy- 
dride and other reactions of a similar nature. 

Phthalic anhydride is produced in America almost exclusively by this proc- 
ess. Naphthalene is volatilized in an air stream and passed over the cataljrst. 
The reaction begins at about 300^ and attains a maximum yield at about 400 to 
450", equaling about 50% of the theoretical. [Gibbs, /. Ind, Eng, Chem^ zz, 1031 
(1919)]. 

Vanadium compounds have been extensively employed in the production of 
aniline black. [Pinknet, Brit, pat, 2745 of 1871, See Chem. News, 33, 116 
(1876)]. 

Austerweil (U. S. pat. 979,247 (1910); C A,, 5» 972) used vanadium com- 
pounds in solution to catalyze the oxidization of bomeol to camphor by nitric 
acid. — H. D. Gibbb. 

>* Recently the oxidation of benzene vapors by air in the presence of 
vanadium pentoxide has assumed commercial importance as a method for manu- 
facturing maleic acid, Weiss and Downs, /. Ind. Eng, Ckem., za, 228 (1920), 
U, 8. patents 1318,631-:^-3, Oct. 14, 1919, C, A., Z4, 70; Can. pat, 192,766, Sept. 
10, 1919, C, A,, Z3, 2683. — E. E. R. 

*« Johnson, English patent 17,424 of 1911; /. 80c, Chem, Ind., 31, 772 (1912). 

*7 Farbw. MmsiSR^ Lucros and Bat^NiNG, English patent 10|377 of 1914, 
/. 80c. Chem. Ind., 33* 061 (1914). 



97 OXIDATIONS 264 

The use of cerium oxide permits acetic acid being made from ace^- 
tylene in one operation by effecting the hydration (309) and oxidation 
simultaneously. It is sufficient to circulate a mixture of 130 parts 
acetylene and 80 to 100 parts oxygen through a mixture of 400 parts 
glacial acetic acid, 100 parts water, 50 parts merciuic nitrate, and 
10 parts cerium oxide kept between 50 and 100^.'^ 

262. Anthracene can be transformed directly into anthraquinone 
by gaseous oxygen under pressure and in the presence of catalysts.'* 
Osmium peroxide in the small amount of 0.05% realizes this oxida- 
tion rapidly with oxygen imder 10 atmospheres pressure.^ The same 
result can be obtained by keeping anthracene suspended in 30 parts 
water containing a little ammonia and 0.5 part copper oxide for 20 
hours at 170® with compressed oxygen." 

The mixture of oxides remaining from the manufacture of 
Welsbach incandescent mantles has been proposed as a catalyst for 
direct oxidation.** 

263. Metallic Chlorides. Anhydrous aluminum chloride, AlCls, 
causes the direct fixation of atmospheric oxygen by aromatic hydro- 
carbons. Benzene gives a certain amount of phenol and toluene 
yields w.cresole.*' 

264. Manganous Salts. As has been stated in Chapter III (153), 
manganous salts are active agents of direct oxidation, particularly in 
water solution. This activity persists whatever be the acid constit- 
uent of the salt; it is observed in the salts of mineral acids, in the 
acetate, butyrate, benzoate and oxalate: it is sixteen times as great 
in the succinate as m the nitrate. We can assume that the manganous 
salt is partially hydrolyzed in water solution and that the resulting 
manganous hydroxide is oxidised to the dioxide by one atom of an 
oxygen molecule, the other oxidising the organic compound. The 
nascent manganese dioxide, in turn, would part with its extra oxygen 
to another portion of the organic compound and the manganous 
hydroxide thus regenerated would begin the cycle again. A trace 
of the manganous salt would thus be able to oxidise an unlimited 
amount of the oxidisable substance.** 

m 

»» Drbtfus, French patent 479,856, /. 8oc. Chem. Ind., 35, 1179 (1916). 

** The best catal3rst yet found for oxidising anthracene to anthraqiiinone is 
vanadic oxide. The conditions are about the same as for the oxidation of 
naphthalene to phthalic anhydride. — H. D. Gibbs. 

^ HoFMANN, Berichte, 45, 3329 (1912). 

*i German patent^ 292,681. 

" Mason and Wilson, Proc, Chem, Soc, ax, 296 (1906); C, 1906 (1), 395. 

«sFbiedil and G^rafts, Ann. Chim, Phys. (6), X4, 435 (1888). 

««Bbbtban]>, BvU. 80c. Chim, (3), X7. 753 (1897). 



266 CATALYSIS IN ORGANIC CHEMISTRY 98 

Cerium salts may frequently act similarly (163). 

265. Oxidation of Oils. The bleaching of oils can be effected 
by a moderate oxidation with warm air in the presence of catalytic 
oxides which doubtless act after being transformed into metcdlic 
soaps, the true decolorizers. 

Palm oil through which a current of air is passed at 80-90^ is 
bleached in four hours if 0.2% manganese borate is added. The same 
oil with 0.1% cobalt borate is bleached in 3.5 hours by the passage 
of less than its own volume of air. With the same proportion of 
nickel or iron borate, about three times as much air and 10 hours 
are required.*' 

If the operation is carried on in an autoclave with compressed air, 
the addition of 0.02% of cobalt soap permits various oils to be 
bleached perfectly and rapidly.** 

266. The so-called drying oils, such as linseed and poppy seed, 
have the property of rapidly becoming thick in contact with air, 
which oxidises them, converting them< into resinous substances which 
are almost insoluble in boiling alcohol. It has long been known that 
this drying power, depending on the oxidisability, is greatly increased 
by incorporating with the oils small proportions of salts of lead and 
particularly of manganese, the important accelerating agent appearing 
to be the metallic soap formed with the oil.*^ 

The metallic soaps that are the most active are those containing 
metals which are capable of several degrees of oxidation, particularly, 
cobalt, manganese, cerium, lead, chromium, iron, and uranium, while 
soaps containing bismuth, aluminum, mercury, and thallium are less 
active.** 

The direct oxidation of oils is retarded by moisture and accelerated 
by light. Elevation of temperature and increase of the pressure of 
the oxygen increase the velocity of the oxidation.** 

267. Metallic Silicates. Silicates can sometimes be substituted 
for the corresponding oxides. Kaolin (aluminum silicate) causes the 
union of hydrogen and oxygen at 230'^.** 

« Sastbt, /. Chem, 8oc., 107, 1828 (1916). 

*• Rai, /. 80c, Chem. Jnd., 36, W8 (1917). 

*^ LiVACHB, CompL rend., 124, 1620 (1897); C, 1897 (2), 332. 

^ Magkbt and Inoub, /. Sac, Chem. Ind., 36, 317 (1917). 

«• FoKiN, Z. angew, Chem., aa, 1451 (1909). 

** JoANNis, Compt. rend., 258, 501 (1914) ; C. A., g, 1866. 



99 OXIDATIONS 269 



II. -* Oxidations Carried Out with Oxidising Agents 

268. Oxidations by Hydrogen Peroxide. The oxidation of or- 
ganic compounds by hydrogen peroxide can be advantageously cat- 
alyzed by small quantities of jerrous or jerric salts (acetate) ."^ 

Methyl, ethyl, propyl, butyl, isobvtyl, and isoamyl alcohols are 
oxidised to a mixture of alddiyde and acid, the acid being more 
abundant when ferrous oxalate is used than with the sulphate. The 
addition of wood charcoal favors the production of aldehyde. Man- 
ganous salts can be substituted for the iron."' 

Glycol furnishes glycoUc aldehyde without any glyoxal.^* 
Olycerine reacts vigorously to give glyceric aldehyde, along with a 
little dihydroxy-acetone^* Arabite yields an araboketose and 
dtdcite, galactose,^^ Malic acid passes into oxaiacetic add, HG^C .- 
CO . CH, . CO,H." 

Benzene is partially transformed into phenol and then to pyro^ 
catechol;^'' p.hydroxybenza$dehyde, HO.CeH4.CHO, gives proto- 
catechuic aldehyde,^^ 

Amines likewise undergo a regular oxidation to the corresponding 
aldehydes when they are warmed above 60** with hydrogen peroxide in 
presence of a ferrous salt; ethyktmine saving acetaldehyde; isoamyU 
amine, isovaleric aldehyde; bemylamine, benzaldehyde, while amino* 
ethyl alcohol is changed, above 30^, to a mixture of gly colic aldehyde 
and glyoxal.^^ 

The use of the double cyanide of copper and potassium permits 
the oxidation of morphine hydrochloride by hydrogen peroxide to 
dehydromorphine and psevdom^orphine.^ 

Furfural in alcoholic beverages can be destroyed slowly by the 
addition of 1% hydrogen peroxide and 0.01% m^anganese acetate.^^ 

269. Oxidation by Nitric Acid. Vanadium pentoxide, employed 

(»^ Fbmton, /. Chem, Sac., 65, 899 (1894). 

«s DoROSHBvsxn and Babdt, J. Russian Phya, Chem. Sac, 46, 754 (1914) ; 
C. il., 9, 1865. 

B* Ebnton and Jackson, /. Chem, 80c., 75, 575 (1899). 

M Fbnton and Jackson, Ibid,, 75, 1 (1899). 

Bs Nbxjbbbg, Berichte, 35, 962 (1902). 

(^« Fbnton and Jonbs, /. Chem. Sac, 77, 69 (1900) and 79, 91 (1901). 

BY Cbobs, Bevan and HaxBiBa, Berichte, 33f 2015 (1900). 

** SoMMBB, Oerman paUnt, 155,731, C, 1904 (2), 1631. 

^^ SuTO, Bioehem. Zeitschr., 71, 169 (1915); C. A., 9, 3059. 

^ DmsicAa, Bull 80c, Chim. (4), 9, 264 (1911). 

«i Chauvin, Arm. Falsif., 6, 463 (1913) ; C. A,, B. 981. 



269 CATALYSIS IN ORGANIC CHEMISTRY 100 

in the ratio of 0.1 g. to 50 g. cane sugar and 500 cc. nitric acid (density 
1.4) causes the complete oxidation of the sugar in 20 to 30 hours in 
the cold to oxalic acid without the formation of saccharic, mucic, 
tartaric acids, etc., as by-products. Above 70^, carbon dioxide and 
water are obtained instead of oxalic acid.*' 

In the presence of mercuric nitrate, nitric acid oxidises anthracene 
to antkraquinone. The reaction is finished in three hours if 117 parts 
anthracene suspended in 300 parts nitrobenzene are wanned to 30^ 
with 460 parts 31% nitric acid in which three parts of mercury have 
been dissolved.*' 

In the nitration of aromatic compoimds by mixtures of nitric and 
sulphuric acids, the presence of a mercuric salt has no influence, but 
wiUi nitric acid of density 1.3, it causes oxidation along with nitra- 
tion or the substitution of a nucleus hydrogen by the phenolic hy- 
droxyl group. Thus benzene, toluene, and ethyl-benzene give nitro- 
phenols. It is possible to prepare 2,4-dinitrophenol and picric acid 
by heating benzene on the steam bath under reflux with 8 times its 
weight of nitric acid, density 1.3, and 15% mercuric nitrate. The 
oxidation must precede the nitration, since nitrobenzene is not oxidised 
by this treatment.** •■ 

** Naumann, Mobsbr, and Lindbnbaum, /. praki. Chem. (2), 75, 148 (1907). 

«« U. 8. patent, 119,546. 

M WoLLrBNSTsiN and B&nmB, Berichte, 46, 586 (1913). 

^' In addition to vanadium and mercury compounds, a number of other 
substances have been found to accelerate oxidation by nitric add. Disregarding 
the mechanism of reaction, oxides of nitrogen and nitrous acid may be con- 
sidered as catalysts for oxidation by nitric acid. For instance, Vsurr (Proc. Roy, 
80c., 48, 458-9 (1891) ) found that the presence of nitrous acid initiated the oxi- 
dation of copper, mercury and bismuth by 20% nitric acid. Oxides of nitrogen 
are mentioned a number of times in the patent literature as being necessary or 
desirable for the purpose of starting oxidation of organic compounds by nitric 
acid, especially in the manufacture of camphor. Molybdenum compounds, 
salts of manganese, iron, cerium and palladiiun, and even salts of calcium and 
magnesium have, under various conditions, been found to accelerate oxidations 
by nitric acid. Probably, in many cases, the acceleration produced by foreign 
substances is due to the reducing action of the substance on the nitric acid, with 
consequent formation of oxides of nitrogen. Thus the Commercial Research 
Company proposes to start the oxidizing action of nitric acid on aromatic hydro- 
carbons with side chains by means of formaldehyde, copper, zinc, starch or other 
reducing substance (BriL Pat^ 141^33 (1920) ). 

Nitration by means of nitric acid is likewise accelerated by dissolved oxides 
of nitrogen. Klemznc and Ekl (Monatak. 39, 641-98 (1918) ) studied the nitra- 
tion of a number of phenol derivatives and concluded that pure nitric acid, 
free from dissolved nitrogen peroxide or nitrous acid, does not cause nitration. 

HoLOBRMANN (BeHchte, 39, 1250 (1906) ) obtained negative results in efforts 
to influence the position of the entering nitro-groups by nitrating in the pres- 






* • • •• • 

> > C « M • 



t • '• 



101 OXTOATIONS .-. 2tl 

270. Oxidations by Hypochlorites. The'ftddflSoii* ctf ' a"-v6ry 
small amoiint of a cobalt or nickel salt to a solution of an alkaline 
h3rpochlorite, or chloride of lime, caiises the evolution of oxygen in 
the cold.«« 

This oxidising mixture may be used for oxidising organic sub- 
stances. It transforms o,nitrotoluene into cnitrobenzcddehyde and 

By the same means, phenanthridene is oxidised to phenanthri- 
done: •• 

CeH4-CH C«H4-C0 

and acridine into acridone: 

271. Oxidations by Chlorates. The oxidation of aniline hydro- 
chloride, in the preparation of aniline black, is carried out in the cold 
by a solution of potassium or sodium chlorate with the aid of metal 
catalysts, the most active of which is vanadium pentoxide, VjOg, of 
which one part is sufficient for 270,000 parts of aniline and the corre- 
sponding amoimt of chlorate. Salts of cerium and, to a less extent, 
those of copper and iron are useful catalysts but less powerful. 

Osmium peroxide, O8O4, is at least as powerful as vanadium pent- 



ence of cat&lystB, but an appreciably greater yield of dinitrobensene, from nitro- 
bensene, was obtained by nitrating with, rather than without, a small amount 
of mercuric nitrate, under conditions otherwise similar (28.0% and 23i»% of 
theory respectively). Also, Holdermazm obtained evidence that mercuric ni- 
trate acts as catabrst in Hie nitration of beta-methylanthraquinone. For the 
control of the position of the entering nitro-group, the use of considerable quan- 
tities of different adds mixed with the nitric acid is more promising than the 
use of smaU amounts of metal salts. See Tinglb and Blanck (/. Amer. Chem, 
80c,, 30, 1305 and 1687 (1908) ). 

Additional data on simultaneous nitration and oxidation in the presence of 
mercury compounds are given by Wolffsnstbin and Paab (Berichie, 46, 689 
(1913) ) and Vionon (BvU. 80c. Chim., 27, 647-^ (1920) ). There are also a 
number of patents on this subject. Silver, copper and aluminum salts are said 
to act as catalysts as well as mercury. — A. S. Ricbabdson. 

^ Flutmann, Annalen, 134, 04 (1866). 

*Y Badibchi, Oerman patent, 127,388, C, xgos (1), 160. 

«« Picmr and Fjokt, BerichU, 26, 1962 (1893). 



» » • • r • 

• • • • • , 



• • 



272 .CATi^YSIS m ORGANIC CHEMISTRY 102 

oxide' tLnd ite* xn^* makes it possible to oxidise anthracene to anthra- 
quinone by means of chlorates.** 

272. Oxidations by Sulphur Trioxide. Fuming sulphuric acid 
is frequently used as an oxidiser for organic compoimds, the trioxide 
being reduced to the dioxide, but its action is not rapid enough in the 
absence of metallic catalysts, the most active being mercuric sulphate 
between 290 and 390^.^^ The sulphates of potassium, magnesium, 
manganese, and cobalt are without effect, while those of nickel and 
iron act feebly. Only the sulphate of copper can replace that of mer- 
ciuy in practice but it is disadvantageous. It should be mentioned 
that a mixture of the sulphates of copper and mercury is more active 
than the two taken separately .^^ 

It has been proposed to add to the sulphuric acid the mixture of 
the rare earths (oxides of cerium, lanthanium, etc.) which is a by- 
product in the manufacture of thorium nitrate, but this has not proved 
to be of any advantage.^* 

In the Kjeldahl method for estimating nitrogen in organic com- 
pounds, the substances are boiled for a long time with fuming sul- 
phuric acid. During the oxidation of the carbon and hydrogen, all 
the nitrogen passes into ammonia which is retained by the sulphuric 
acid without being burned. The addition of 0.5% mercuric sulphate 
triples the speed of the oxidation.^' In practice, 1 to 2 g. of mercury 
to 20 cc. acid is used for 5 to 7 g. of sample to be analyzed. 

273. The chief application of oxidation by fuming sulphiu'ic acid 
is the preparation of phthalic add from naphthalene, a reaction which 
is the basis of one of the methods for making artificial indigo.^^ 
When naphthaline is moderately heated with the acid, sulphonation 
takes place, }mt above 200^ oxidation sets in. At 275^ the oxidation 
rate is quintupled by 1% of mercuric sulphate.^" 

274. In the presence of mercuric sulphate, fuming sulphuric acid 
can oxidise anthraqvinone and fmiiher oxidise the hydroxyanthra- 
quinones first formed. Thus anthraquinone and 1-hydroxyanthra- 
quinone give quinizarine, l,4-Ci4He02(0H)2.^* 

At 200-250°, alizarine gives quinalizaririe, l,2,6,8-Ci4H402(OH)4, 

^ HorMANN and Schumfblt^ Berichte, 48, 816 (1915). 

70 Gbakbb, Berichte, 29, 2806 (1896). 

71 BiODDiG and Bbown, Z. physik, Chem., 46, 502 (1903). 
7s DiTZ, Chem. Zeii., 39, 581 (1905); C, 1905 (2), 485. 
7s Wnj'ARTH, Chem. Centr., X885, 17 and 113. 

7« Badischb, Oerman patent, 91^. 

7s This procees is being replaced by the high temperature air oxidation 
process. See note to 260 supra. — H. D. Gibbs. 
7« Wackbb, /. prakL Chem. (2), 54, 88 (1896). 



103 OXIDATIONS 277 

and l|3,5,7-tetrahydroxyanthraquiiioiie heated with 20 parts of sul- 
phuric acid of 66^ BS. to the same temperature in the presence of 0.05 
part mercuric sulphate, yields 1,3,4,5,7,8-hexahydroxyanthraquinone 
or anthracene blue. The addition of boric add greatly favors these 
reactions. 

275. Oxidations by Permanganates. The oxidation of aliphatic 
alcohols by potassium permanganate in presence of ferrous sulphate 
readily gives aldehydes but, on the contrary, in the presence of ferrous 
oxalate, the adds are formed quantitatively.^^ 

276. Oxidations by Persulphates. The persvlphates of the alka- 
lies mixed with nitric acid and a small quantity of silver nitrate are 
useful for oxidising organic compounds. The active agent is a silver 
peroxide or pemitrate which is constantly regenerated by the per- 
sulphate.^* 

Benzene is transformed into quinone by this means, and oxalic add 
is burned to carbon dioxide. Quinone is broken up into a number of 
products among which is foimd maleic addJ^ 

277. Oxidations by Nitrobenzene. In the dye industry nitro' 
benzene is frequently used as an oxidising agent, being reduced to 
aniline; the presence of ferrous salts aids in these oxidations. 

^7 DoBOSHBvsKn and Babdt, /. Russian Phys. Chem, Soc, 46, 754 (1914) ; 
C. A,, 9, 1865. 

T» Kbmpf, Berichte, 38, 3063 (1906). Babohdvsxt and Kuzma, Z. Elektroch., 
Z4, 196 (1908). 

79 Ebmpf, BerichU, 39> 3715 (1906). ' 



CHAPTER VI 
VARIOUS SUBSTITUTIONS IN MOLECULES 

§ I. — INTRODUCTION OF CHLORINE, BROMINE 

AND IODINE 

Chlorinations 

278. The presence of anhydrous chlorides is a great aid in the 
direct chlorination of organic compounds, whether the chlorides are 
added as such or as the elements which are immediately transformed 
into the chlorides by the chlorine. There is no need to distinguish 
between these two. 

Iodine or Iodine Chloride. Iodine, or iodine monochloride, in 
presence of an organic substance and of chlorine is changed to the 
trichloride which gives up chlorine to the organic substance, being 
itself reduced to the monochloride which starts all over again. With 
2 to 12% of iodine it is easy to chlorinate benzene,^ toluene^ the 
xvlenes,^ etc., and also to transform carbon disulphide into carbon 
tetrachloride.* * 

The chlorine compounds thus obtained are always mixed with 
a small amount of iodine derivatives formed by catalytic induction. 

279. Bromine. This can catalyze chlorinations in tiie same 
manner as iodine, particularly in the preparation of carbon tetra- 
chloride from the disulphide, but its use is less advantageous. 

280. Sulphur. The immediate chlorination of sulphur by chlo- 
rine to several degrees of chlorination makes of it a good chlormating 
agent of moderate activity which gives excellent results in some 
cases. Thus to transform acetic add into chloracetic, chlorine is 

1 M^UMBL, /. Chem. Soc., is, 41 (1802) ; Jahreab., z86a» 414 and z864» 524. 
JuNGFLXiscH, Ann, Chim, Phya. (4), 1$$ 180 (1808). 

> Bklstbin and Gsitnkb, Annden, Z39, 334 (1800). Limpbicht, Ibid., Z39» 
320 (1800). H«BNEB and Majbbt, BerichU, 6, 790 (1873). 

s WoLLBATH, Zeit. f. Chem., z866, 488. ERtiGEB, Berichte, z8» 1756 (1885). 
Elugb, Ibid., z8, 2099 (1885). Koch, Ibid., 33, 2319 (1890). 

* English patent, 18^ of 1899. 

* With iodine as a catalyst, the reaction may be stopped at the inteiv 
znediate stage, CI3CSCI, though with iron, caibon tetrachloride is formed at 
once. (Hbusich and Rbid, /. Amer. Chem. Soc, 43, 593 (1921)). — E. E. R. 

104 



105 VARIOUS SUBSTITUTIONS IN MOLECULES 282 

passed into the boiling acid containing a small amount of sulphur. 
In two hours 8 parts of acetic acid are changed to 10 parts chloracetic 
containing but little acetyl chloride. In the cold, with a little sul- 
phur or sulphur chloride, only acetyl chloride is obtained.^ 

281. Phosphorus. Red phosphorus can be substituted for sul- 
phur in the preparation of chloracetic acid (280). 

The presence of phosphorus trichloride greatly facilitates the 
formation of benzyl chloride from toluene. By passing a current of 
chlorine into 100 parts of boiling toluene containing 1 part phos- 
phorus trichloride (as far as possible in the sunlight)/ 80 parts of 
the desired product are obtained in eight hours. 

282. Charcoal. Wood charcoal readily causes the chlorination 
of hydrogen to hydrochloric acid without explosion. By passing a 
mixture of equal voliunes of carbon monoxide and chlorine throi^ 
a long tube filled with fragments of charcoal, carbonyl chloride is ob- 
tained.® Animal black gives even better results, a 30 cm. tube being 
sufficient." ^^ 

A charcoal made by calcining blood with potassium carbonate 
can serve as a catalyst for the chlorination of organic substances 
between 250^ and 400^. The progressive and complete chlorination 
of ethyl chloride can thus be readily obtained.^^ 

Carbon can likewise serve as a catalyst in the preparation of 
carbon tetrachloride from carbonyl chloride by a kind of auto-chlori- 
nation: 

2COCl,-CO, + CCl4- 

The carbonyl chloride vapors are passed through a succession of 
towers filled with coke or ardmal charcocd^^ 

« AuGBB and BAhal, BuU. 8oc. Chim. (3), 3» 145 (1889). Rusbanot^ /. RuB' 
9ian Phys. Chem. 8oc., 1891, 1, 222; BerichU, 35, Ref. 334 (1882). 

T n sunlight 18 used no other catalyst is required. The chlorine reacts as 
fast as it can be passed in, even at 0*. — E. E. R. 
a ScmBL, Jahretb., 2864, 350. 
• Patbino, Gat. Chim. Ital., 8, 233 (1878). 

10 Using 10 g. charcoal prepared £rom ox bones, Atkinson, Hbtoock and 
Pora (/. Chem. 80c., 2x7, 1410 (1020) ) caused carbon monoxide and chlorine to 
combine at 40 to 50* as rapidly as the mixture could be passed into the U-tube 
containing the catalyst. After the preparation of 10 k. of phosgene this catalyst 
had lost none of its activity. 

They found the activated charcoal from Army box respirator to 
be more active still, it being extremely efficient even at 14*. Even 
at 50* this catalyst does not cause the fonnation of hydrogen chloride in mix- 
tures of chlorine and caifoon monoxide containing hydrogen. — £. £. R. 
^^ Damoisbau, Compt. tend., 83, 00 (1876). 
» U. 8. patent, 808,100. 



283 CATALYSIS IN ORGANIC CHEMISTRY 106 

283. Metallic Chlorides. Activity is possessed by the chlorides 
of polyvalent metals which have several degrees of chlorination, 
such as iron, thallium, molybdenum, antimony, tin, gold, vanadium, 
uranium, etc., and also by aluminum chloride and to a certain extent 
by zinc chloride but not by the chlorides of the alkaline or alkaline 
earth metals or of nickel, cobalt, manganese or lead.^' 

Moisture is usually unfavorable to their action. 

284. Alumintmi Chloride. Anhydrous aluminum chloride, or 
(duminum turnings, is an excellent chlorination catalyst.^^ It readily 
realizes the transformation of carbon disulphide into carbon tetra- 
chloride.^' The addition of 3% of it to benzene permits the progres- 
sive introduction of chlorine, going from the monochlor- to hexachlor- 
benzene.*'' 

A mixture of equal volumes of chlorine and carbon monoxide 
passed over fragments of anhydrous aluminum chloride at 30-^^, 
is partially transformed into phosgene. The yield is better when the 
mixture of the gases is passed into chloroform saturated with alumi- 
num chloride.^* 

285. Ferric Chloride. A little ferric chloride, for which may be 
substituted iron scale, iron sesquioxide or sulphide, ferrous carbonate, 
or even iron sulphate, gives good results with the substitution of 
chlorine in aromatic compoimds. 

By using one part ferric chloride and one of iron powder to 300 
parts of benzene, one obtains a yield of 335 parts of monochlor- 
benzene with 37 parts of poly-chlor-.^® *® 

i> WniLGBRODT, /. prakL Chem. (2), 34, 264 (1885) and 35f ^1 (1887). 

^« Sbbug, Armalen, 237, 178 (1887). 

^^ GoLDSCHMiDT and JjARSBN, Z. physik, Chem., 48, 424 (1904). Bobnwatbs 
and HoLUSMAN, Bee, Trav, Chim. Pays-Baa, 31, 221 (1012). 

i« MouNBYRAT, BtUl. Soc. Chim. (3), zg, 262 (1898). 

^7 MouNETRAT and PouBBT, CompL rend., 227, 1026 (1898) ; C, 1899 (1), 199. 

i» Plotnikov, /. Russian Phys. Chem. 80c., 48, 457 (1916). 

^® Fahi^ebo, List A Co., German patent, 219,242. 

*^ It is usually assumed that the action of ferric chloride depends on the 
pol3rvalenQy of iron, supposing that a part of its chlorine is abstracted by the 
bensene leaving ferrous chloride which then combines with free chlorine to re- 
generate the ferric chloride. 

In order to find whether benzene actually takes chlorine away from ferric 
chloride the following experiments were tried in my laboratory by H. K. Parker. 
Ferric chloride was sublimed, as it was formed, into a dry flask which was re- 
peatedly evacuated to remove free chlorine. To this ferric chloride, 100 g. of 
bensene was added and kept at 40"* for 30 ho\u«, after which water was added. 
No chlorine was found in the bensene layer. The water layer contained 2.90 g. 
ferric chloride and 0^ g. ferrous. Into a similar mixture of ferric chloride and 
benzene^ dry chlorine was passed at 40* for 2 hours and extensive chlorination 



•107 VARIOUS SUBSTITUTIONS IN MOLECULES 288 

It is equally satisfactory for the chlorination of toluene '^ or the 
xylenes.** 

The use of ferric chloride facilitates the commercial preparation 
of carbon tetrachloride from carbon disulphide: 

C& + 3CU-&CI1 + CCI4 

because it catalyzes the chlorination of the carbon disulphide by the 
sulphur chloride according to the equation: 

CS, + 2S,Cli-6S + CCl4. 

The reaction commences at 60^ and is continued at the boiling tem- 
perature of the mixture.** ** 

28$. Molybdenum Chloride. Molybdenum chloride, MoCl^, is 
an excellent catalyst in the aromatic series and, when used to the 
amoimt of 0.5%, permits successive stages of chlorination. Its use 
is of no advantage in the aliphatic series.**^ 

287. Antimony Chlorides. The chlorides of antimony (which 
can be replaced by the powdered metal or by the oxide) are frequently 
employed as carriers in chlorinations. They are more active than 
iodine and permit the complete chlorination of benzene.** 

They are useful in transforming carbon disulphide into the tetra- 
chloride.*^ 

The successive use of iodine and of antimcmy pentachloride 
enables us to pass directly from benzyl chloride to hexachlor' and 
heptachlortoluene^^ 

288. Tin Chloride. Stannic chloride (which can be replaced by 
the metal or the oxide) can also give good effects.** Its action, as 



took place. At the end there was 30 g. benzene still unchlorinated and treat- 
ment with water showed only 0.04 g. ferrous iron. 

These experiments show that the reduction of ferric chloride by a large 
excess of benzene is very slight. It seems to me best to regard the action of 
feme chloride as analogous to that of aluminum chloride in this reaction, see 
note to 157.— E. E. R. 

» Sebug, Anruden, 237, 152 (18S7). 

*> Glaus and Bubstibt, /. prakL Chem, (2), 41, 552 (1890). 

ss MtiAMR and Dubois, German patent, 72,099. EngKsh patent, 19,628 of 
1803. 

M With iron as catalyst, it is impossible to stop at the intermediate, 
d.QSCl."— E. E. xl. 

>B Abonhbim, Berichte, 8, 1400 (1875). 8muQ, Annalen, 237, 152 (1887). 

s« M^LLBB, Zeit. Chem, Pharm,, 1864, 40. 

*^ HoFMANN, Annalen, 1x5, 264 (1860). 

** BmiSTBDr and Kuhi^ebo, Annalen, X50, 306 (1860). 

s» P^mcou, BvU. 80c. Chim. (3), 3> 189 (1890). 



289 CATALYSIS IN ORGANIC CHEMISTRY 108 

without doubt is the action of all chlorides used to aid direct chlori- 
nations; is proportional to its concentration.*^ 

289. Aluxninum Bromide. Its use permits the direct prepara- 
tion of perchlorethane, 001^ . CGI,; starting with acetylene tetrabro- 
mide, CHBr, . CHBrj, or with ethylene bromide.*^ 

Brominations 

290. Anhydrous chlorides and bromides are more or less active 
agents in bromination just as in chlorination. The hydrobromic acid 
produced in the reaction is the product most readily followed.** 

291. Iodine. Iodine, or rather iodine bromide, which is the im- 
mediate product, is frequently used and leads especially to the 
bromination of the aromatic nucleus.** 

292. Manganese. Powdered metallic manganese is an excellent 
catalyst for the bromination of benzene, toluene, and xylene. With 
3 g. of the powdered metal and bromine, 18 g. benzene is completely 
converted into monobrombenzene in 90 hours in the cold, without the 
metal suffering any appreciable attack.*^ The slight traces of bro- 
mide formed on the surface are doubtless sufficient to catalyze the 
reaction. 

293. Aluminum Chloride. A small proportion is sufficient to 
effect the regular bromination of most organic compounds. Thus 
1 g. can cause the bromination of 120 g. benzene.** 

We may put alongside of the brominations catalyzed by aluminum 
chloride the migration, which it causes, of the bromine of tri- 
bromphenol to benzene,** or toluene,*^ which are thereby trans- 
formed to brombenzene or m.bromtoluene with the production of 
phenol. 

Aluminum bromide causes a regular bromination of toluene.** 
Zinc Chloride and Bromide. Zinc chloride or metallic zinc 
which is changed to the bromide may be effective.** 

^ GoLDBCHMiDT and Labsbn, Z. physik. Chem., 48, 424 (1904). 

s^ MouvsTBAT, BvU. 8oe. Chim. (3), zg, 262 (ISdS). 

»« GusTAvsoN, /. prakt. Chem. (2), 6a, 281 (1900). 

** Rnuvr and Aixm, Berickte, 8, 1287 (1875). Ja£X>B8BN, Ibid., 17, 2372 
(1884) and z8, 369 (1885). Bbumb, Chem. Cent., 1900 (2), 257. 

M DucuuBZ, Gat, and Raynaud, BvU. 80c. Chim. (4), 15, 737 (1914). 

>• Frma, Armalen, zaz, 361 (1862). LnoT, BvU. 80c. Chim. (2), 48, 210 
(1887). RoTTX, Ann. Chem. Phys. (6), zd, 347 (1887). 

s< KoHN and M&um, MonaUh. Chem., 30, 407 (1909). 

>7 KoHN and Bum, Ibid., 33> 923 (1912). 

»• GusTAvsON, /. Ruuian. Phya. Chem. 8oe., 9, 286 (1877). 

^ 9cBiAPABBUJ, Gag. Chim. Itd^ x;» 70 (18S^), 



109 VARIOUS SUBSTITUTIONS IN MOLECULES 296 

Ferric Chloride or Bromide. Ferric chloride or finely divided 
iron (which changes to the bromide) is a good bromination catalyst.^ 

CH, - CHBr 
Cyclobutene bromide, • • , brominates in the presence of 

CHj - CHBr 

iron powder to tetrabrombtUane, the ring being opened.^ 

Mercuric Chloride or Bromide. These may be used as bromi- 
nating agents/' Without doubt tiie simultaneous formation of 
aluminum and mercuric bromides is the cause of the remarkable 
activity of akiminum amalgam as a bromination catalyst/' 

Introduction of Iodine 

294. The direct introduction of iodine into organic molecules is 
very difScult but may sometimes be accomplished by the aid of ferric 
chloride, as is the case with benzene. The yield of iodide thus 
formed is low.** 



§ a. — ADDITION OF SULPHUR 

295. Anhydrous aluminum chloride can cause the addition of sul- 
phur to benzene at 76-80^. Thiophenol, CeHg.SH, and products 
derived from it, phenyl sulphide and phenylene sulphide, are thus 
obtained.** 

296. The direct sulphuration of diphenylandne, by heating the 
amine with sulphiur, requires a temperature of 200 to 265^ for 6 to 8 
hours: *• 

yCeHs yC«H4V 

NHT + 2S = HsS + S( )NH. 

In the presence of iodine the reaction is complete in 10 minutes at 
185^, giving a quantitative yield of thiodiphenyl-amine instead of 
50 to 60%. Thiodinaphthyl amines, etc., are also prepared in good 
yields.*^ 

^ ScmBNnLBN, Anndlen, 231, 164 (1885). 

^ WiumlTna and Bbuci, BerichU, 40, 3979 (1907). 

^2 Lazassw. 

«* CoBBN and Dakin, /. Chem, 8oe., 75, 893 (1899). 

** LoTHAB Mbtub, Annalen, d3Z» 195 (1885). 

M FsoDBL and Cbaftb, BuU. 80c. Chim. (2), 39, 306 (1883). 

** Bdnthsbn, Annalen, 930, 77 (1885). 

*^ KscmmsAcmj, J. prdkt. Chem. (2), 89, 11 (1914). 



297 CATALYSIS IN ORGANIC CHEMISTRY 110 

§3. — ADDITION OF SULPHUR DIOXIDE 

297. Benzene warmed with aluminum chloride absorbs sulphur 
dioxide readily giving benzene svlphinic add, C^B.^ . SO2H. *• The 
reaction is accelerated by the presence of hydrochloric acid and is 
doubtless due to the formation of an unstable addition product which 
reacts with the benzene in the presence of the aluminum chloride 
and hydrochloric acid.*" > 

§4. — ADDITION OF CARBON MONOXIDE 

298. The direct addition of carbon monoxide to hydrocarbons is 
an exceptional reaction which can be realized in only a small number 
of cases. However, the use of aluminum chloride or bromide makes 
it possible with aromatic hydrocarbons. 

A mixture of carbon monoxide and hydrogen chloride is passed 
for several hours into benzene containing almninum chloride and 
10% cuprous chloride at 40 to 50**. 

It can be assumed that the carbon monoxide dissolves on account 
of the cuprous chloride and forms f ormyl chloride, H . CO . CI, which 
then reacts as an acid chloride on the benzene in the presence of 
aluminiun chloride (891). We have in the end: 

CeHe + CO — CeH^ . CHO. 

The yield is 90%. ^^'^ Likewise from toluene and aluminum chlo- 
ride, p.toluic aldehyde, CH, . C^H^ . CHO, with a yield of 73%;" 
0. Xylene gives, by the same method, 1,2 dimethyUbenzaldehyde(4). 
p.Xylene and mesitylene give analogous results.** 
The presence of the cuprous chloride and the hydrogen chloride 
seem to be superfluous and it is sufficient to cause the carbon mon- 
oxide \mder pressures of from 40 to 90 atmospheres to act on the 
benzene in the presence of aluminum chloride and a little hydrogen 
chloride."' 

^« Fbiedel and Chafts, Ann. Chim. Phys. (6), Z4» 443 (1888). 

^^ Knobvknaoel and Kbnneb, Berichte, 41, 3315 (1908). Andrianowbki, 
Bull 80c. Chim. (2), 31, 199 and 495 (1879). 

*o HflPoaMATSEi, /. Russian Phys. Chem. 80c. 33, 154 (1901); C, xgoz (1), 
1226. 

^^ Gattermann and Koch, Berichte, 30, 1623 (1897) and Gattermann, Ibid., 
31, 1149 (1898). English patent, 13,709 of 1897. 

"' Batkb and Co., Chem. Cent., zSgS, 932. Habdinq and Ck)HEN, /. Amer. 
Chem. 80c., 33, 594 (1901). 

^* English patent, 3,152 of 1915; /. 80c. Chem. Ind., 35> 384 (1916). 



Ill VARIOUS SUBSTITUTIONS IN MOLECULES 301 

§ 5. — INTRODUCTION OF METALLIC ATOMS 

Formation of Alcoholates 

299. Alurninum alcoholates are formed by the direct action of 
aluminum amalgam on alcohols thoroughly freed from water.'^ But 
the presence of a catalyst enables them to be prepared directly from 
aluminum. It is sufficient to add a little mercuric chloride, iodline 
or even ethyl iodide. Thus ordinary absolute alcohol readily gives 
aluminum ethylate, AUGCsHb),, a tolid melting at 134^ which can 
be isolated by distilling at 15 nun. pressure.^' 

Production of Mixed Organo-Magnesium Compounds 

300. The production of mixed organo-magnesium compounds from 
organic halides is equivalent to the addition of the magnesium atom 
to the organic molecule: 

Mg + RBr = MgC 

\Br. 

This reaction is usually carried out in anhydrmis ether which 
plays the rdle of catalyst in their formation. It is possible to carry 
out the reaction in benzene in the presence of a small unount of ether. 
Without doubt, we have in succession: 

CiHsv /R 
RBr + (C*H,),0 = y>( 

CfH^ \Br 
and then: 

C*H»\ /R /R Xyit 

X + Mg = Mg( + 0( 
CH*/ NBr \Br \C»Ht 



regenerated 

The regenerated ether can repeat the first reaction. 

301. The ethyl ether as catalyst can be replaced by other ethers, 
amyl ether, etc., or even by a small quantity of a tertiary amine such 
as (hmethyl aniline, the reaction taking place in benzene, toluene, 
hexane, or ligroine. In this case the temporary addition product 
would be: " 

CeHjv /R 

chAn/^ 

CEt^ NBr. 

"^ TiBTCHaNKO, /. Ruuian Phys. Chetn. 80c,, 31, 483 (1899). 
"" MmsTBB, Lucius and Bb^nino, German patent, 286,596; /. 80c, Chem, 
Ind., 34, 1168 (1915). "« Tschkunzdt, BerichU, 37, 4534 (1904). 



302 CATALYSIS IN ORGANIC CHEMISTRY 112 

302. The formation of organo-magnesium halidea is easy with 
organic bromides or iodides but it is greatly facilitated by the pres- 
ence of a suitable catalyst, iodine, hydriodic acid or an alkyl iodide 
such as ethyl iodide. 

The addition of such catalysts is indispensable for the formation 
of these derivatives from aliphatic or cycloaliphatic chlorides, but 
even with this assistance they can not be prepared from aromatic 
chlorides. 

According to 2ielinski, iodine and magnesium produce in 
anhydrous ether some of the compound, Mglj. 2 (02115)20, which he 
was able to isolate and which would start the reaction.'^ 

303. A certain number of substances hinder the formation of the 
organo-magnesium compounds. We may mention anisol, ethyl ace- 
tate, chloroform, and carbon disulphide which act as negative 
catalysts (11). 

304. For the preparation of mixed organo-zinc compounds, Blaise 
uses pure ethyl acetate as a catalyst instead of ether and operates 
in a toluene or petroleum ether solution. Actually one-third of a 
molecule of ethyl acetate is used for one molecule of the alkyl 
iodide.** 

"7 Zbunski, /. Russian Phys. Chem. Soc, 35> 3d9 (1903). 
S8 Blaisb, Bull. 80c. Chim.f 1011, Conference, 7. 



CHAPTER VII 
HYDRATIONS 

305. Hydration reactions can be separated into two distinct groups 
according to whether the water is added without splitting the mole- 
cule or whether the addition of the water causes the original molecule 
to break up into two or more new ones. 

As examples of the first group we have the addition of water to 
unsatiurated hydrocarbons giving alcohols or ketones, or to nitriles 
and ifmidea. 

Reactions of the second class are more frequent, such as the 
saponification of esters, the decomposition of acetals and glucosides, 
the hydrolysis of amides, oximes, hydrazones, semicarbazones, etc. 

More or less concentrated mineral acids are very powerful agents 
for realizing the various hydration reactions, whether in concentrated 
form, they give rise to unstable temporary addition products which 
decompose to form the hydration products and to regenerate the acids, 
or whether they act in dilute solution in consequence of their elec- 
trolytic dissociation, the chief factors being the hydrogen ions so 
liberated. 

Water solutions of the strong bases, either the alkalies or alkaline 
earths, can often realize hydrations which water alone can usually 
accomplish but at a much slower rate or a much higher temperature. 

z. — Fixation of Water by Addition 

306. Ethylene Compounds. Moderately concentrated sulphuric 
add enables us to add, in the cold, a molecule of water to isobutylene, 
(CH,),C:CH„ to give trimethyUcarbinol, (CH,) , . CX)H.* • By 
adding amylene, little by little, to a mixture of concentrated sulphuric 
acid and ice, diluting with ice water, washing with soda, and dis- 
tilling the product, dimethyl-ethyl carbinol is obtained with a yield 
of 85 to 92% of the amylene.* 

Likewise 3-methylpentene, CH, : CH . CH(CH,) . CH, . CH„ adds 
water to give the corresponding tertiary alcohol. 

1 BuTiAOW, Annalen, 144, 22 (1867). 

* Isopropyl alcohol is now manufactured by absorbing in sulphuric acid 
the propylene from the gases resulting from the cracking of heavy hydro- 
carbons.— E. E. R. 

* Adams, Eamm, and Mabvbl, /. Amer, Chem. 8oc^ 40, 1950 (1918). 

.113 



307 CATALYSIS IN ORGANIC CHEMISTRY 114 

With 85% Bulphuric acid hexene^l and heptener-S give the 
secondary alcohols, accompanied by a certain amount of the sulphuric 
acid esters, while the 100% acid only polymerizes tiie hydrocarbons/ 

At 45^ sulphuric acid effects the addition of water to iso-oletc 
add which is changed to hydroxystearic acid? 

307. Dilute vitric add provokes the rapid hydration of pinene, 
CioH^ey ^^ alcohol solution, at the ordinary temperature to form 
terpine, CjoHgoO,. • 

Hydrochloric add also can cause the addition of water. By 
digesting for three hours in the light a mixture of aroton aldehyde, 
CHg . CH : CH . CHO, and hydrochloric acid, the aldol, /S-hydroxy- 
butyric aldehyde, CH, . CH(OH) . CH, . CHO, is formed.^ 

308. Doubly Unsaturated Compounds. Acetylene hydrocarbons 
and their aUerdc isomers can add water in the presence of sulphuric 
acid and other catalysts to give ketones: 

R.Ci C.R' + H2O = R.CO.CHa.R' 

R\ /R" R\ yR" 

and ;C:C:CC + HaO = )CH.CO.CHC 

R'/ \R'" R'/ \R'" 

With suiphvric add, the reaction is carried out by dissolving the 
hydrocarbon in the cold concentrated acid and pouring this solution 
inmiediately on to ice.® 

The mechanism appears to be the formation of an unstable sul- 
phuric acid derivative which decomposes on contact with water to 
form an unsaturated alcohol which' immediately isomerizes into the 
ketone. Thus with ethyl-acetylene, we should have successively: 

^H, 
CH,.CH,.C:CH + H2SO4 = CH,.CHaCf 

\O.SOsH 

CHs.CHj.C^ * =H2S04 + CH8.CHi.C(OH):CH, 
XO.SOH 

CHj.CHjCCOH) :CH2 = CHjCHj-COCH,. 

In the case of true acetylene hydrocarbons, the product is a methyl 
ketone. With disvbstituted acetylenes, two isomeric ketones are ob- 
tained. This is the case with methylamylacetylene? 

^ Brooks and Humphrey^ Ibid., 40, 822 (1918). 
« Saytzbsff, /. prakt, Chem. (2), 37, 284 (1888). 
« WiGGBRS, Armalen, 57, 247 (1846). 
7 WtlBTZ^ BvU. 80c. Chim. (2), 49, 286 (1884). 

• BiHAL, B\M, 80c, Chim, (2), 47, 33 (1887). 

• B£hal, Ibid. (2), 50, 360 (1888). 



115 HYDRATIONS 312 

Acetylene should give acetaMehyde, but this condenses with loss 
of water (795) and crotordc aldehyde is the chief product.^® 

309. Water solutions of mercuric salts, the chloride, bromide, and 
sulphate, cause the same formation of ketones in consequence of the 
temporary production of combinations of the hydrocarbon and the 
salt, which are then decomposed by water. Thus aUylene, CH, .- 
C : CH, gives acetone, CH3 . CO . CHa- 

Acetylene behaves normally, yielding acetaldehyde:^^ 

CH : CH + H2O = CHa.CHO. 

Acetylene is absorbed at 25 to 45^ in a solution of mercuric oxide 
in water containing 45% 01: less sulphuric acid, or 25% phosphoric 
acid. The solution saturated with the gas is warmed to 80 to 100^ 
when acetaldehyde is given off. The solution is then cooled and 
made to take up more gas and so on. By a number of repetitions 
the mercuric salt produces 20 times its own weight of acetaldehyde.^* 
A stronger solution of sulphuric acid is unfavorable as it would cause 
the formation of crotonic aldehyde and other condensation products. 
(See the direct formation of acetic acid (261).) 

310. This hydration of acetylene to acetaldehyde can likewise be 
accomplished by passing the moist gas over zinc, nickel, or ferrous 
oxides at 300^. There is the formation of a certain amoimt of acetal- 
dehyde and also of crotonic aldehyde. If the moist acetylene con- 
tains ammonia, the formation of acetaldehyde is shown by the deposit 
of crystals of aldehyde ammonia}^ 

311. Nitriles. Nitriles dissolved by gentle warming in sulphuric 
add diluted with 20% of water, are transformed into amides. The 
same transformation can be effected also by caustic soda and potash; 
but, especially if the operation is carried on in alcohol solution in 
the neighborhood of 100°, the hydration may go so far as to break 
the amide down into ammonia and the acid, which is at least partially 
neutralized by the alkali. 

312. Imides. It is the same way with imides, sucdrdmide, 

CHj-COnv 

— ylnH, warmed with a small amoimt of baryta water, gives 

CH,-CO/ 

at first amido'sucdnic acid, H^N . CO . CH, . CH, . CO^H," the 

further hydration of which yields sucdnic add. 

" Bbbthblot, CompL rend,, laS, 336 (1899). 
" KuTSCHEBOFP, Berickte, 17, 13 (1884). 
" Dbmsytvb, French patent, 487,411 (1918). 

i» Chichibabinb, /. Russian Phys. Chem. 80c., 47, 703 (1916) ; C. A., 9, 2612 
(1916). 

" TsncHmr, AnndLen, Z34» 136 (1866). 



313 CATALYSIS IN ORGANIC CHEMISTRY 116 

HiN.CH-COv 
Likewise aspaiiic imide; | yNH, heated to 100^ with 

CH,-CO/ 

aqueous ammomcLf adds a molecule of water to give (UfparagiM, 
HOOC . CH, . CH(NH,) . CONH,.» 

Acetaldehyde in water solution causes cyanogen to add two mole- 
cules of water to form axamide, HjN . CO . CO . NH,.** 

II. — Hydrations with Decomposition 

313. A hydration which results in the decomposition of the mole- 
cule is usually called hydrolysis. 



§1. HYDROLYSIS IN WATER SOLUTION 

Hydrolysis of Esters. The hydrolysis of esters is known as 
aapomfication. 

When a water solution of methyl acetate or ethyl acetate is kept 
in the cold, there is a slow decomposition by water to give the alcohol 
and free acid: 

CHj.COi.CiH, + H,0 - CHs.COjH + CiHj.OH 

The reverse reaction of esterification tends to reform the ester so 
the decomposition is never complete; the reaction tends to an equi- 
librium, the more water there is present, the more ester will be de- 
composed, but this limit is not reached at ordinary temperatures till 
after some years. In several days, the amount of ester decomposed 
is only about 1%. On the contrary, if a small amoimt of hydro- 
chloric acid, or other strong acid, be added to the mixture, the reaction 
becomes very rapid, the limit being reached in 24 hours. 

Furthermore, the acid added is in no way changed. It is entirely 
precipitated by silver nitrate which shows that it has not formed an 
appreciable amoimt of ethyl chloride. Up to a certain limit, the 
saponifying power of the acid is proportional to its concentration; 
and for different acids, at the same molecular concentrations, the 
saponifying power is proportional to the strength of the acid which 
is measured by its electrolytic dissociation, and consequently this 
activity is defined by the number of hydrogen tons in a unit volmne 
of the solution. Hydriodic, hydrobromic, nitric and chloric acids, 
which are strongly ionused, are consequently powerful catalysts, and 
so is sulphuric add which is most commonly used for this purpose. 

^" EonNKB and Mbnozzi, Gag. Chim. Ital., Z7» 173 (1887). 
!• LuBiG, Annalen, 1x3, 246 (1880). 



117 HYDRATIONS 318 

314. This action is general and applies equally well to the saponi- 
fication of fats which are esters of glycerine with the fatty acids. 
A fat heated with water and 4% sulphuric acid to 120^ is completely 
hydrolyzed in 12 hours, 42% of the fatty acids being liberated in the 
first hour. To produce a like decomposition with water alone re- 
quires heating to 220^ in an autoclave.^^ 

315. In very dilute solutions the velocity of saponification is the 
same with hydrochloric, hydrobromic, hydriodic, nitric, chloric and 
methyl sulphuric acids of the same acidity and is proportional to the 
concentration of the acid. 

It is the same for all the esters of a given organic acid with dif- 
ferent primary alcohols.^* 

316. On the other hand, the velocity changes greatly when the 
organic acid from which the ester is derived is changed. Thus for 
ethyl esters the saponification velocity of the formate is 25 times 
that of the acetate, 50 times that of the iaobutyrate, 100 times that 
of the valerate, and 4,000 times that of the bemoate. 

317. The presence of neutral metallic salts modifies the velocity, 
chlorides accelerating the saponification by hydrochloric acid,^* while 
sulphates retard the action of sulphuric acid. 

Pressure may also have an effect; in the case of the saponification 
of methyl acetate by hydrochloric acid, pressure increases the velocity. 

318. The soluble bases, potassium, sodium, barium, and calcium 
hydroxides have an analogous effect which, at first sight, would be 
attributed to the afl^ty of the base for the acid liberated, were the 
amount of ester saponified not disproportionate to the amount of base 
reacting. The real reason for the saponification is again foimd in 
the dissociation of the bases in dilute solution into ions. 

The saponification of fats has given clear evidence on this point. 
The amoimt of lime required to saturate all of the fatty acids of a 
fat is about 9.7%, and in practice might reach 12 to 14%, but experi- 
ence shows that 1% is sufficient for complete saponification in water 
at 190^ under 12 atmospheres pressure, while 3% produces this result 
in 8 to 10 hoiurs, at 170^ and 8 atmospheres.*^ 

It appears from the above figures that, in spite of the additional 
energy liberated by the combination of the bases with the acids, the 
catalytic activity of the bases is less than that of the strong acids. 

^7 iBWXOwrrecB, Conjir. h la 8oc. Chim,, 1900, 12. 
^* L5wBNmEBZ, Z. phy8. Chem,, 15, 305 (1804). 

1* Tnrr, /. pnkt. Ckem. (2), 34, 353 (1886). Emm, Z. phya. Chem., 39, 
348 (1900). 

^ IPWXOWITBCH^ loc. CU; p. 8. 



319 CATALYSIS IN ORGANIC CHEMISTRY 118 

319. For different strong bases, in very dilute solution and at tiie 
same concentration, the saponification velocity is independent of the 
nature of the base, whether it be potassium, sodium, barium or cal- 
cium hydroxide, but is proportional to the concentration of the base. 

For esters derived from the same acid, the velocity changes 
greatly with the alcohol, thus methyl acetate is saponified twice as 
rapidly by caustic soda in the cold as is isobutyl acetate*^ The 
influence of the nature of the acid is less than it is in saponification 
by strong acids. Thus when methyl esters are saponified by caustic 
soda at 14^, the velocity for the acetate is about double that for the 
isobutyrate, six times that for the isovalerate, and quadruple that 
for the benzoate. 

In the saponification of ethyl acetate by bases, the presence of 
neutral salts cuts down the velocity.** 

320. The saponification of chlorine derivatives is not usually pos- 
sible, but benzal chloride and benzotrichloride are hydrolyzed to 
benzaldehyde and benzoic acid by water alone when heated under 
pressure. 

The saponification of benzal chloride, CeHsCHCl,, by water alone 
requires a temperature of 140-160°." In the factory it is usually 
effected by means of milk of lime. In the presence of iron powder, 
the reaction can be carried out at 90-95°.*" 

It is the same way with benzotrichloride which is readily trans- 
formed into benzoic acid in the presence of iron, ferric chloride, 
oxide or hemoate?^ 

321. Ethers. Water alone breaks up ethers into two molecules 
of the alcohols very slowly.** The addition of small quantities of 
sulphuric acid greatly accelerates the reaction.*^ 

322. Acetals. Acetals can be regarded as mixed ethers derived 
from alcohols and the unstable gylcols of which aldehydes and ke- 
tones are the anhydrides. Their hydrolysis cannot be accomplished 
by water alone, nor by alkalies, even when hot. On the contrary, 
it is easily effected by boiling with either dilute hydrochloric acid 
or with sulphuric acid diluted with four volumes of water, the alde- 
hyde and the alcohol being set free. 

323. Polysaccharides. Polyoses and polysaccharides such as 
sucrose, lactose, maltose, trehalose and even starch, dextrine and 



>^ Abshbnius, Z. phys. Chem., z, 110 (1887). 

32 LiMPBiCHT, Annalen, Z39, 319 (1866). 

2^ ScHUurzB^ German patent, 82,027. 

s« LnsBN, Annalen, 165, 136 (1873). 

s« EBUBNMETEa» Zeit. /. Chemie, 4, 343 (1868) 



119 HYDRATIONS 326 

cellulose can be regarded as ethers or acetals involving the many 
alcohol groups and the aldehyde or ketone groups of the simple 
hexoses. Their hydrolysis into the simple sugars can be realized 
more or less readily by the aid of small quantities of acids as 
catalysts. 

324. The inversion of cane sugar, that is, its complete hydrolysis 
into glucose and fructose, can be brought about by traces of mineral 
acids and is, perhaps, the earliest catalytic reaction to be observed.'* 
Hydrochloric, sulphuric, or even oxalic add can be used and the 
velocity of the hydrolysis is proportional to the concentration of the 
hydrogen ions resulting from the electrolytic dissociation of the acid. 
Concentrated sugar solutions are rapidly inverted by traces of acid. 
A solution containing 80 g. sugar to 20 g. water, with the addition 
of 0.004 g. hydrochloric acid, is completely inverted by boiling for 
an hour.^^ Even carbonic acid can cause this reaction, slowly in the 
cold, rapidly when heated. A sugar solution saturated with carbon 
dioxide and heated for an hour in a sealed tube is completely in- 
verted.** 

The velocity of the inversion of sugar by strong acids is increased 
by the addition of neutral salts.^^ 

When the reaction is carried on in alcohol solution, the velocity 
varies considerably with the proportion and nature of the solvent.*® 
Increase in the concentration of the sugar increases the velocity.*^ 

High pressure diminishes the velocity of inversion by hydrochloric 
acid, the diminution being about 1% for 100 atmospheres.*' 

325. The hydrolysis of maltose is slower than that of cane sugar, 
requiring at least three hours of boiling with 3% sulphuric acid.** 

Trehalose is slowly hydrolyzed into glucose by warming with 
dilute sulphuric acid.** 

326. Sulphuric acid diluted with 33 parts of water is used in the 
commercial preparation of glucose by the hydrolysis of starch at 
100^ for three hours. The addition of a little nitric acid to the sul- 

s« CxAMSNT and Dbsormes, Ann. Chim. Phys., 59, 329 (1806). 

57 WoHL, Berichte, 93, 2086 (1890). 

58 LiPPMANN, Berichte, 13, 1823 (1880). 

2* Spohb, Z. phynk. Chem,, 2, 194 (1888). Arrhbnius, Ibid,, 4, 226 (1889). 
ExjiMR, Ibid,, 32, 348 (1900). 

w BuRBOws, /. Chem, 80c,, X05, 1280 (1914). 

*^ RosANOFF and Pottbb, /. Amer. Chem, 80c,, 35, 248 (1913). 

s> RdNTOBN^ Wiedemumn'a Annalen (3), 45> 96 (1892). Rothmund, Z. 
physik. Chem,, do, 170 (1896). 

» Mezssl, /. prakt. Chem, (2), 95, 120 (1882). 

*^ M^NTZ, JcJiresber,, 1873, 829. BiSTHMxyr, Ann, Chim, Phya. (3), 55, 
272 (1859). 



327 CATALYSIS IN ORGANIC CHEMISTRY 120 

phuric acid seems to shorten the time required. There is an inter- 
mediate formation of dextrine which is, in turn, hydrolyzed by the 
dilute acid. 

327. Glucosides. The various substances designated by this name 
are numerous among vegetable products and have a constitution anal- 
ogous to that of the polysaccharides. Their hydrolysis by pure 
water can usually be accomplished only by heating to high tempera- 
tiures in sealed tubes, but by boiling with dUute mineral adds, they 
are decomposed into a sugar (usually glucose) and one or more sub- 
stances of various kinds. 

The action of acids is comparable to that of soluble ferments, such 
as emtdsine, but is more rapid and more drastic, the product of hy- 
drolysis being sometimes altered by the peculiar action of the acid. 

328. Thus arbvMne when boiled with dilute sulphwric acid is 
hydrolyzed into 1 molecule of glucose and 1 molecule of hydro- 
quinone,'^ which is identical with the results obtained by long con- 
tact with emulsine in the cold. 

Helicine is hydrolyzed by dilute acids into glucose and aalicylic 
aJdehyde,^^ and quercitrine into isodvldte and querdtine (tetrahy- 
droxyflavanol."' 

The ruberythric acid of madder root gives alizarine and 2 mole- 
cules of glucose when boiled with dilute acids.^^ 

329. Salicme heated to 80^ with 10 parts of fuming hydrochloric 
acid (d. 1.25), gives 2 molecules of glucose'* and saliretine, 
(CeH^ . CH2 . OH) 2, while the action of emulsine in the cold or 
boiling with dilute acid leads to saUgenine, 0.HO . CeH^ . CH^OH.^ 

Amygdaline is decomposed by boiling with dilute hydrochloric 
or sulphuric acid, just as it is in the cold by emulsine, into benzalde- 
hyde, hydrocyanic acid, and 2 molecules of glucose: 

C^oH^NOu + 2H,0 = CeH^ . CHO + HON + 2C^K^fi^. 

But when acids are used the hydrocyanic acid formed is rapidly 
hydrolyzed into formic acid and ammonia.^^ 

Coniferine is split by emulsine into glucose and coniferyl alcohol, 
but when the hychrolysis is carried out by boiling with dilute acids, 
the alcohol is resinified.^' 

*« Kawaldb, Annalen, 84, 356 (1852). 

s« Pmu, Annalen, 56, 64 (1845). 

ST RiGAUD, Annalen, 90, 289 (1856). 

*s Gbaebb and Liebbbmann, Annalen, SupL, 7» 296 (1870). 

SB Kraut, Annalen, 156, 124 (1870). 

^ PnoA, Annalen, 56, 37 (1845). 

«^ LuDwiG, Jahreaher., 1855, 699 and 1856, 679, Arch. Pharm, (2), 87, 273. 

^s TiBMANN and Haabmaiyn, Berichte, 7, 611 (1874). 



121 HYDRATIONS 334 

330. The dilute acids can be replaced by dilute soluble bases such 
as sodium, potassium and barium hydroxides or even by a solution 
of zinc chloride (for example with helleborine) .^ 

331. Acidamides and Analogous Compounds. The derivatives 
formed by the loss of a molecule of water between an organic acid 
and ammonia, an amine, hydroxylamine, hydrazine, phenylhydrazine 
or semicarbazid can be more or less readily hydrolyzed into the mole- 
cules from which they were derived. This hydrolysis can be accom- 
plished by mineral acids which combine with the ammonia or other 
base or by aqueous alkalies which unite with the organic acid. 

Amides which can be hydrolyzed by boiling with pure water are 
much more rapidly hydrolyzed by heating with dilute mineral acids 
or with dilute alkalies. 

332. The hydrolysis of oximes takes place on contact with hot 
concentrated hydrochloric acid, which combines with the hydroxyl- 
amine that is liberated along with the aldehyde or ketone. 

Phenfylhydrazonfis are hydrolyzed in the cold with concentrated 
hydrochloric acid which combines with the phenylhydrazine. 

Bisdiazoacetic acid,HOOC . Cf ^C . COOH, is hydrolyzed 

\nh-nh/ 

by sulphuric acid diluted with 4 molecules of water to give 2 mole- 
cules of hydrazine and 2 molecules of oxalic acid.^ 

333. Heating in a sealed tube with a concentrated solution of 
hydrochloric acid causes the hydrolysis of svlphocyanic esters: 

CN.SR + 2H,0 — R.SH + CO. + NHa, 

as well as of mustard oUs, or isosulphocyanic esters: 

CS : NR + 2H,0 — H,S + CO, + H,NR. 

amine 

334. On the contrary, the hydrolysis of isocyanic esters, or alkyl 
carbylamines, is carried out by boiling with aqueous ^ or alcoholic ^ 
notash* 

CO : NR + H,0 - CO, + H,NR, 

and the activity of the base can be attributed to its aflSnity for car- 
bonic acid. 

^* HusBMANN and Mabm^^, AnruUen, 135, 56 (1865). 
M Cubhus and Lang, /. prakt. Chem. (2), 38, 532 (1888). 
*» WuBTZ, Ann. Chim. Phya. (3), 49, 43 (1864). 
46 Hallbb, BiM. 8oe. Chim. (2), 45> 706 (1886). 



336 CATALYSIS IN ORGANIC CHEMISTRY 122 

335. The hydrolysis of amides and of alkyl amides can be carried 
out by acids or alkalies indifferently. In the case of aliphatic amides, 
the reaction is usually effected by heating with alcoholic potash or 
soda and takes place slowly, sometimes requiring heating for several 
days. We have: 

R.CO.NH, + H,0 — R.CO^H + NHa, 

and we may believe that the affinity of the potash for the acid deter- 
mines the reaction. 

336. In most of the above reactions the catalytic r61e of the acids 
and bases does not appear, at first sight, to be well established. We 
can, however, assume that it is really catalytic, since in the reactions 
that have been most closely studied, such as the hydrolysis of amides, 
amounts of acid far less than equivalent to the amides greatly accel- 
erate the reaction. In the case of the hydrolysis of acetamide by 
dilute mineral acids, it has been foimd that the activity of the acids 
is proportional to their ionization and to the concentration of the ions 
in the system.*^ 

§ a. — HYDROLYSIS IN GASEOUS SYSTEMS 

337. The Saponification of Esters. Titania, TiO,, which readily 
causes the esterification of alcohols by aliphatic acids (767) , between 
280 and 300^, just as readily reverses the reaction and brings about 
the saponification of esters by water. The rapid passage of a mix- 
ture of water and ester vapors in equivalent amoxmts over the oxide 
at 280 to 300^ is sufficient to reach about 30% hydrolysis and this 
percentage is increased as the relative amoimt of water is increased 
till practically complete hydrolysis is effected by very large amounts 
of water. " 

Thoria can produce the same effect but with less activity .^' 

338. Ethers. Thoria, ThO,, which effectively catalyzes the forma- 
tion of phenyl oxide, (CeH5)20, from phenol at 400 to 500^, can 
equally well decompose it when phenyl ether and water vapor are 
passed over the heated oxide, the decomposition reaching 50%.^* 

339. Hydrolysis of Carbon Bisulphide. The reaction of water 
vapor on carbon disidphide in the presence of appropriate catalysts, 
such as ferric oxide, can be considered a case of hydrolysis. The re- 
action is incomplete but goes in this direction: 

CS, -f- 2H,0 ^ COa + 2H2S. 

*T OsTWAii), /. prakt. Chem, (2), 27, 1 (1883). 

** SABATiBt and MaUjHI, Compt. rend., Z52, 494 (1011). 

«• Sabaiibb and Ebpui, BvU, 80c. Chim. (4), 15, 228 (1914). 



123 HYDRATIONS 841 

This reaction applied to illuminating gas suppresses 67% of the 
carbon disulphide which it contains and, if the hydrogen sulphide is 
absorbed as rapidly as it is formed, all of the carbon disulphide is 
eliminated.'^ 

III. — ALCOHOLYSIS 

340. The action of alcohols on esters can be compared to the sapon- 
ification of esters by water and is likewise catalyzed by small quanti- 
ties of strong mineral acids, hydrochloric and sulphyric^^ 

If a primary aliphatic alcohol, R'OH, is mixed with the ester de-. 
rived from an acid, RCOOH and a complex alcohol, MOH, we shall 
have: •* 

R.CO.OM + R'.OH — MOH + R.CO.OR'. 

The alcohol, MOH, is set free. This is what takes place when 
methyl, ethyl, propyl alcohols and the like attack the esters of bomeol, 
glycerine, etc., in the presence of a minute amount of hydrochloric 
acid. 

Thus bomyl acetate in a methyl alcohol solution, containing 1% 
hydrochloric acid, is rapidly decomposed into bomeol and methyl 
acetate. 

Olycerides dissolved in absolute alcohol containing a few per cent 
of hydrogen chloride yield glycerine and the fatty acid ethyl esters.'* 

341. Haller has designated these saponifications which take place 
readily with all the fats, by the name of alcoholysis. They can be 
carried out by mixing 100 g. of a fat with 200 g. dry methyl alcohol 
containing 1 or 2 g. hydrogen chloride and heating on a steam bath 
under reflux till the mixture becomes homogeneous. If necessary 

^ GiOLLBT, 8oc, Tech. de Vlnd, da gaz en France, 19x8, 245. 

"^ Sodium alooholate is an even better catalyst than hydrochloric acid. In 
the transformation of methyl benzoate into the ethyl ester, sodium ethylate 
was found to be about 4,000 times as efficient as an equivalent amount of 
hydrochloric acid. (Rkd, Amer, Chem, J., 45, 506 0911) ). — E. E. R. 

"* This reaction is a perfectly general one and simple alcohols may be re- 
placed as well as '* complex/' thus methyl alcohol replaces ethyl and vice vena 
as shown by Risd (Amer. Chem. J., 45, 479 (1911) ), and recently by Rbimsb 
and DowNSS (7. Amer. Chem. Sac, 43, 945 (1921) ). 

For a number of references on alcoholysis see article by Pabdbb and Bsm 
(/. 2nd. and Eng. Chem., la, 129 (1920) ). It is a reversible reaction, the 
equilibrium point depending on the concentrations and activities of the two 
alcohols competing for the acid and hence can never be complete, no matter 
how much one alcohol predominates. — E. E. R. 

"* RocHLBDBB, Annolen, 59, 260 (1846). Bbbthblot, Ann. Chim. Phya. (3), 
4Z, 311 (1854). 



341 CATALYSIS IN ORGANIC CHEMISTRY 124 

more hydrogen chloride may be added during the reaction. The mix- 
ture is finally poured into brine which dissolves the glycerine and 
causes the methyl esters of the fatty acids to separate as a top layer .^ 
This reaction is rapid with cocoa butter ^^ and cantor oil, with 
which heating for several hours is sufficient,"* and is slower with 
drying oils such as Unseed.^^ It goes just as well with ethyl, propyl, 
and isobutyl alcohols."* 

^* Bauxr, Compt. rend,, 143, 057 (1906). 

'" Hallbb and Youbsovffian, Compt. rend,, 143, 803 (1906). 

"* Halubb. Compt. rend., X44t 462 (1907). 

'7 Hallbb, Compt. rend., 146, 259 (1908). 



CHAPTER VIII 

HYDROGENATIONS 

HYDROGENATIONS IN GASEOUS SYSTEM, 
GENERALITIES, USE OF NICKEL 

342. Historical. The catalytic properties of finely divided plati- 
num discovered by Davy and Doebereiner at the beginning of the 
nineteenth century, have shown its power to cause oxidations. Sev- 
eral chemists attempted to apply the special powers of platinum 
sponge to other reactions and particularly to the direct addition of 
hydrogen to various substances. In 1838, Kuhhnann showed that 
nitric oxide, or the vapors of nitric acid, warmed with hydrogen in 
the presence of platinum sponge gave anmionia.^ In 1852, Coren- 
winder observed that the same agent caused hydrogen to combine 
rapidly, though incompletely, with iodine between 300 and 400^.' 
In 1863, Debus, with the aid of platinum black, accomplished the 
addition of hydrogen to hydrocyanic acid to form methyl amine,* and 
foimd that ethyl nitrite is transformed into alcohol and ammonia 
under the same circumstances. In 1874, von Wilde succeeded in 
transforming acetylene into ethylene and then into ethane, by plati- 
num black at room temperature.^ 

343. In a series of investigations continued since 1897, Sabatier 
and Senderens (1897-1905), then Sabatier and Mailhe (1904-1908), 
and Sabatier and Murat (1912-1914) have established and extended 
to a large number of cases a general method of direct hydrogenation 
of volatile organic compoimds, based on the use of finely divided 
catalytic metals and particularly on the use of nickel recently reduced 
from the oxide.' 

1 KuHLMANN, Compt. rend., 7» 1107 (1838). 

* CoRBNwmnEB, Ann. Chim. Phys. (3), 34* 77 (1852). 
s DsBus, Annalen, laS, 200 (1863). 

♦ VON WttDB, Berichte, 7f 362, (1874). 

' These invefltigations have been published in a large number of original 
articles of which more than 50 are in. the (Ik>mpte8 Rendus de I'Academie des 
Sciences as well as in various collective memoirs of which the chief are: Sabatixb, 
Vth Congress of Pure and Applied Chemistry, Berlin, 1904, IV, 663. Sabatibb 
and ^NDiBBNS, Confer. 80c. Chim., Paris, 1905. Sabatibb, Rev. Gen. 8c., x6» 
842 (1905). Sabahsb, Rev. Gle. Chim., 8, 381 (1905). Sabatier and Sbndbrinb, 

125 



344 CATALYSIS IN ORGANIC CHEMISTRY 126 

As early as 1902 this new method was taken up in many French 
and foreign laboratories and numerous chemists have contributed, 
along with the above authors, to widen its application. 

344. Essentially the process consists in passing the vapors of the 
substance mixed with hydrogen over a layer of the catalytic metal, 
platinum bUick, or even nickel, cobalt, iron, or copper reduced from 
the oxides in the same tube in which the hydrogenation is to be car- 
ried on, maintained at a suitable temperature, sometimes room 
temperature but more commonly somewhere between 150 and 200^. 
A temperature aroimd 180® is very frequently found to be the most 
suitable. 

Of the five metals mentioned above, nickel is the most active and 
it and cobalt are the only ones capable of effecting certain hydro- 
genations such as that of the benzene nucleus. Copper is less power- 
ful and platinum and iron are between cobalt and copper. 

345. The apparatus employed by Sabatier and his co-workers 
comprises: 

1. A hydrogen generator. 

2. A working lube to contain the catalytic metal. 

3. An arrangement for introducing the vapors to be hydrogenated 
along with the hydrogen. 

4. A receiver to collect the product of the reaction. 

346. The Hydrogen Generator. The hydrogen can be prepared 
by the action of commercial hydrochloric acid diluted with half its 
volume of water on ordinary granulated zinc. The continuous gen- 
erator of Sainte-Clair Deville consists of two large flasks of 10 to 
15 1. of which the lower tubulures are connected by large rubber tub- 
ing. One flask is filled with granulated zinc and the other witii hydro- 
chloric acid. The gas is washed with strong caustic soda and then 
with concentrated sulphuric acid. A graduated safety tube in the 
acid wash bottle serves to indicate the gas pressure. Between the 
two wash bottles is a stop cock to regulate the gas and beyond the 
acid wash bottle is a pinch cock for further adjustment of the pres- 
sure. To secure a regular delivery of the gas it is sufficient to main- 
tain the acid in the safety tube at a constant height. On account of 



Ann. Ckim. Pkys. (8), 4* 319 (1905). Sabatibi, Vlth. Congress Pure and AppL 
Chem,, Rome, 1906, Xth. Sect 174. Sabahbb and Mau^he, Ann. Chim. Pkys. (8), 
z6, 70 (1909). Sabatibr, Berichte, 44, 1984 (1911). Sabatier, Address at Stock- 
holm on the reception of the Nobel Prize, Rev, Scient, i, 289 (1913). Sabatibb, 
Confer, k Toulouse au Congr^ du gaz, Le Oaz, 57, 1914. Sabatibb, Confer. 
k University of London, Rev. Gle. Chim., 17, 185 and 221 (1914). Sabatibb and 
MuBAT, Ann. de Chim. (9), 4, 253 (1916). 



127 HYDROGENATIONS 847 

the large dimensions of tiie apparatus, a constant evolution of gas 
can be maintained for at least six hours. 

The hydrogen must be carefully freed from impurities derived 
from the zinc or from the acid (hydrogen sulphide, arsine, phosphine 
and hydrochloric acid vapors). For this purpose it passes through 
a tube of Jean glass, filled with copper turnings kept at a dull red, 
which stops the major part of the impurities. The purification is 
completed by passing the gas through a long tube filled with slightly 
moist fragments of caustic potash which retains acid vapors as well as 
any remaining hydrogen sulphide. The purified gas passes to the 
reaction tube. 

The complete drying of the gas appears superfluous as it has been 
shown that moist hydrogen hydrogenates benzene or phenol, over 
nickel, at least as well as dry.® 

Electrolytic hydrogen, which is on the market in steel cylinders 
at high pressures, can be used to advantage. These cylinders fitted 
with suitable reducing valves, furnish a nearly pure gas which can 
be freed from the small amount of. oxygen which it contains by passing 
over red hot copper in a tube followed by a drying tube containing 
caustic potash. 

347. The Reaction Tube. In a glass tube 65 to 100 cm. long 
and 14 to 18 mm. inside diameter, a longer or shorter (35 to 80 cm.) 
thin layer of platinum black or of the oxide, from which the catalytic 
metal is to be prepared, is spread. The tube is heated in a gas fur- 
nace such as is used for organic combustions but in which the burners 
have wing tips with little holes so that there are a large number of 
little flames equal in size and close together distributing the heat 
evenly. 

The tube is laid in a semicircular trough and rests on a rather 
thick layer of calcined magnesia or fine sand. The temperature is 
taken simply with a glass thermometer graduated to 450^ which is 
embedded in the trough by the side of the tube and which may be 
moved from place to place to test the evenness of the heating. 

The temperature read on the thermometer is always a little lower 
than that in the tube, the difference being greater at higher tempera- 
tures.^ For temperatures around 180 to 200^ the difference is hardly 
more than 10 to 15^, while at 350^ it may be as great as 
35^. The limits between which the reactions go on are usually wide 
enough so that this approximate determination of the temperature is 
sufficient. 

* Sabatbb and Espil, BuU. 8oc. Chim, (4), 15, 228 (1914). 
^ Sabatob and MAn^Hi, Ann, Chim. Phy8. (8), ao, 296 (1910). 



348 CATALYSIS IN ORGANIC CHEMISTRY 128 

348. If more exact determinations are desired a rectangular copper 
oven 12 X 15 X 65 cm. down the centre of which runs a copper tube is 
used. The thermometer and the tube containing the previously pre- 
pared catalysts are placed in this tube side by side. A metallic regu- 
lator contained in a copper tube parallel to the first controls the gas 
and maintains the temperature at which it is set. The copper box is 
filled with a liquid which up to 270^ may be boiled linseed oil, or for 
higher temperatures a mixture of equal weights of sodium and potas- 
sium nitrates which is liquid above 225®. For delicate hydrogena- 
tions with such substances as benzoic esters, Sabatier and Murat 
have employed a massive bronze block, 65 cm. long, 10 cm. wide and 
7 cm. high, of rectangular cross section, with roimded comers. Two 
symmetrically placed holes 25 nam. in diameter run from one end to 
the other of the block : the one contains the tube carrying the nickel 
and the other the metallic regulator which controls the gas supply 
of the furnace. Any desired temperature is thus obtained very 
uniformly on account of the large mass of the good conducting metal. 
On account of this conductivity, the temperature may be raised 
quickly. Small holes parallel to the large ones receive the thermo- 
meters. 

The temperatiure may be first carried to 350® for the preparation 
of the nickel and then lowered to any desired temperature, such as 
180®, for carrying out the hydrogenation. 

In case nickel-coated pumice is used as catalyst (126) a very use- 
ful arrangement is to fill the two limbs of a vertical U-tube with the 
catalyst. This tube may be heated in an air bath to 350® for reduc- 
ing the nickel and then lowered into an oil bath kept at 180® or into 
the vapors of boiling aniline, 185®, for the hydrogenation. 

Heating on the furnace is less regular and requires close attention 
but has the advantage that the interior of the tube may be watched. 

349. Heating by electric resistance may be conveniently employed. 
The reaction tube is surrounded by asbestos paper on which is wound 
a 1 mm. ferro-nickel spiral which, in turn, is surrounded by a second 
layer of asbestos paper. By the aid of suitable resistances the current 
is regulated to show the proper readings on an ammeter. The tem- 
peratiures in the centre of the tube corresponding to various anmieter 
readings are previously determined by experiment.® 

This method of heating has the advantage, as compared to the 
open furnace, that the tube is heated uniformly around its whole 

^ The conditions of the experiment must be exactly duplicated during the 
calibration since otherwise incorrect estimates of temperatures are possible as 
vArying amoimts of heat are removed by varjdng currents of gas through the 
tube. — E. E. R. 



129 



HYDROGENATIONS 



361 



circumference, and, with it it is best to employ nickeled pumice filling 
the whole tube rather than a layer of nickel resting in the bottom.* 

350. Introduction of the Substance. The method of introducing 
the substance to be hydrogenated varies, of course, according to its 
physical state. 

If it is a gas the forward end of the tube containing the catalyst 
carries a two-hole stopper with two tubes, one for the gas and one 
for the hydrogen. The gas is furnished by a continuous generator 
(as with acetylene or carbon dioxide) or by a metal or glass gasom- 
eter into which it is measured in advance (carbon monoxide, propy- 
lene, nitrous oxide), or even by a discontinuous apparatus which can 
be operated sufficiently regularly (as for ethylene, or nitric oxide). 
A wash cylinder with pressure indicator interposed between a stop 
cock and a screw pinch cock as has been described above for hydro- 
gen (346), serves to admit the gas at any desired constant rate. In 
the case of discontinuous generators, a safety valve is arranged by 
having a side outlet tube dipping imder mercury so that the excess of 
gas may escape. 



jfy^^^ 




351. For most Uqvids, Sabatier and Senderens have devised an 
extremely simple apparatus. The liquid is conducted by a capillary 
tube to the interior of the reaction tube. The liquid is placed in a 
large vertical tube T, the lower end of which carries a stopper through 
which passes the vertical portion of a bent capillary tube, the hori- 
zontal portion of which passes through the stopper in the end of the 
reaction tube. 

For a given liquid, the flow is more rapid the larger ihe bore of the 

* Brunei^ Arm. Ckim. Phys. (8), 6, 205 (1905). 



362 CATALYSIS IN ORGANIC CHEMISTRY 130 

capillary tube and the greater the head of liquid, AB. By mam- 
taming this head constant, a regular flow of liquid is obtained. 

It is well to arrange it so that the liquid does not fall from the end 
of the capillary tube in drops, but flows steadily from its end either 
on to the wall of the reaction tube or over the surface of the cork in 
its end. 

The selection of the capillary tube depends on the viscosity of the 
liquid, a smaller tube being used for mobile liquids. 

It is evident that there are two independent ways of regulating 
the flow of the liquid, by changing the diameter of the capillary tube 
or altering its height. Besides, the capillary tube can be fed by a 
reservoir with as large a surface as may be desired and, for experi- 
ments of long duration, the tube A can be placed in commimication 
with a flask of large size in which the variations of level are very slow. 

It is convenient for the stoj^r D to be at some distance from the 
heated portion of the tube ; 3 to 4 cm. is sufficient. The layer of metal 
should not commence for a little distance, about 10 cm. from the 
stopper. The liquid introduced by the capillary volatilizes regularly 
in this open space. It is important to watch that the liquid does not 
wet the catalyst which is frequently altered by contact with the liquid. 

352. We may also operate by bubbling the hydrogen through the 
liquid to be hydrogenated, thus carrying along the vapors. If the 
liquid is very volatile (acetaldehyde, propionic aldehyde, nitrogen 
peroxide, etc.) cooling is necessary so that the amount of the vapors 
carried along will not be too great. 

If the liquid is only slightly volatile, heating may be required, 
always selecting a temperature so that the hydrogen will be in excess 
of that required for complete hydrogenation.** 

353. For solid substances which melt below 100°, the same appa- 

^ In order to get an equimolecular mixture of the vapor and hydrogen, 
the liquid through which the hydrogen is bubbled must be kept at such a tem- 
perature that its vapor pressure is 380 mm. For some liquids this temperature 
may be fotmd from tables in the literature. The vapor pressure curves for 
various classes of liquids are not quite similar, owing to different degrees of 
association, but for most organic liquids, except the lower alcohols, the vapor 
pressure is 380 mm. at from 20 to 24* below their boiling points. To have a 
little more than 1 molecule of hydrogen to 1 of the vapor the liquid should be 
kept at from 25 to 30* below its boiling point. These same liquids have vapor 
pressures approximately one third of an atmosphere at 32 to 36* below their 
boiling points and should be kept at such temperatures to obtain 2 molecules 
of hydrogen to 1 of the vapor or at somewhat lower temperatures if an excess 
of hydrogen is desired, as is usually the case. Similar calculations may be. made 
when a larger number of molecules of hydrogen to one of the compound are 
desired. — E. E. R. 



131 HYDR0GENATI0N8 367 

ratus may be used by Burrounding the capillary tube and the vertical 
tube T with a sort of cylindrical air bath, the lower end of which is 
heated by a Bunsen burner. The current of warm air is sufficient to 
maintain the substance in the liquid condition. This method may 
be used with phenol, the cresoles, the nitronaphthalines and naphtha- 
line. 

A thick copper capillary tube brazed on to a copper vertical tube T 
may be used, and this may be heated directly by a small flame. 

When the substance melts above 100^, it is placed in long porcelain 
boats in the forward part of the tube, a long tube being selected. The 
volatilization of the substance is effected by careful heating, a portion 
at a time, starting from the end next to the heated metal. The re- 
action is of course limited to the amount of material in the boats and 
is consequently intermittent. 

Solids melting below 180^ may be kept fused by a suitable air bath 
and the vapors carried on by the hydrogen which is bubbled through. 

354. When the product of the hydrogenation is a liquid, it is fre- 
quently sufficient to mix some of it with the solid to be hydrogenated, 
thus lowering the melting point so that the usual apparatus for liquids 
may be employed. This is the case with phenol and with ortho and 
meta cresoles. 

The use of solvents which can not be hydrogenated, such as water, 
paraffine hydrocarbons (hexane, heptane, etc.) usually gives poor 
results, particularly when water is used. 

355. Apparatus for Collecting the Reaction Products. If the 
products of the hydrogenation are all ga3es, they are collected at the 
end of the catalyst tube in a gas holder over water, care being taken 
to saturate tiie water with common salt to diminish the solubility of 
the gases. It is well to time the collection of issuing gas in a gradu- 
ated tube. A comparison of the rate at which the gases come out 
with the rate at which they are passed in, frequently gives valuable 
information as to the exact course of the reaction. 

356. If tiie products are partly or entirely Uqvid, the reaction tube 
is connected with a condenser. When the substances are only slightly 
volatile this may be simply a double-necked flask. When the vola- 
tility, at room temperatiure, is considerable, a U-tube is employed 
from the bottom of which a tube leads down into a flask in which tiie 
liquid collects. The U-tube is placed in an inverted tubulated bell- 
jar which is filled with cold water, ice, or a freezing mixture. The 
gas issuing from the other limb of the U-tube is collected over water 
and measured. 

357. Solid reaction products are collected by prolonging the re- 



368 CATALYSIS IN ORGANIC CHEMISTRY 132 

action tube and cooling the further end. The tube should be long 
enough to project a considerable distance from the furnace and the 
end should be inclined downward so that condensed liquids will not 
nin back towards the catalyst. 



HYDROGENATIONS BY MEANS OF NICKEL 

358. In Chapter II the conditions have been described under which 
nickel may be used to advantage as a catalyst for hydrogenations 
(53) , and methods have been given for obtaining a metal of excellent 
catal3rtic properties. Nickel reduced at a red heat below 700^ is 
capable of effecting all sorts of hydrogenations and in particular 
can hydrogenate benzene to cyclohexane;^^ but that reduced above 
750°y or which has been heated to that temperature after having been 
reduced at a lower, is incapable of hydrogenating benzene, is no longer 
pyrophoric and does not gain in weight when exposed to cold air. 
It is then capable of only certain hydrogenations, such as the reduc- 
tion of nitro derivatives. ^ 

359. As has been stated above (112), the presence of chlorine, 
bromine, or iodine, even in traces, in the metal paralyzes its catalytic 
activity. An oxide prepared by precipitation from the chloride can 
not be used, but good results can be obtained with an oxide produced 
by calcining the sulphate at a red heat. 

Whatever care one may take, it is never possible to avoid all the 
causes of poisoning the metal catalyst and particularly in consequence 
of the progressive fouling of the metal which is more or less rapid ac- 
cording to the work done with it, a gradual diminution of the catal3rtic 
power, its aenUeacence, so to speak, is noticed. 

360. Darzens believes that nickel exists in three forms, a, j3, and y. 
The very active y form is said to be obtained by reduction below 260** 
and is considered unstable, remaining in metastable state below 260°. 
Above that temperature it passes into the less active P nickel, then 
at a bright red into the a form which is entirely inactive for hydro- 
genations.*^ According to this author the power to hydrogenate ben- 
zene belongs exclusively to y nickel, which is contrary to the observa- 
tions of Sabatier and Espil quoted above. These transformations of 
y nickel, rapid at high temperatures, would take place slowly even 
at low temperatures and would explain the senilescence of the metal 
apart from many poisoning effects.*' 

^0 Sabatibr and Espn., Bull Soc, Chim, (4), 15, 779 (1914). 
^1 Dabzknb, Btdl. Soc, Chim, (4), 15, 771 (1914). 
IS Dabzbnb, Compi, rend,, 139, 809 (1904). 



133 HYDROGENATIONS 364 

361. Choice of Reaction Temperature. A given hydrogenation 
can be realized only within a well-defined temperature interval. 

In practice^ a lower temperature limit is set by the necessity of 
maintaining in the vapor state in the reaction tube, not only the com- 
pounds to be transformed but also the products of the reaction. 

To a certain extent elevation of temperature accelerates the re- 
action and consequently raises the proportion of the substance hydro- 
genated diuring its passage through the tube. But beyond a certain 
limit, sometimes not far above the temperature at which the reaction 
begins, there is a profound modification of the phenomenon, it being 
possible to completely reverse the reaction in some cases. Thus the 
hydrogenation of benzene may be accomplished as low as 70°, and 
it increases in velocity as the temperature is raised till a maximum is 
reached at 180-200°. Then it decreases till 300° is reached, at which 
benzene is no longer hydrogenated, but, on the contrary, cyclohexane 
is decomposed into benzene and hydrogen. 

362. By hydrogenating around 300°, the aromatic nucleus remains 
almost unaffected while any unsaturated side-chains are hydro- 
genated.^* Thus styrene, CJifiB. : CHg, hydrogenates almost com- 
pletely at 300° to ethylrbenzene, CeHg.CHj.CH,, while if the tem- 
perature be reduced to 180°, liiis is further changed into ethyl" 
cyclohexane, CeHn.CHj.CH,. 

If the temperature is raised above 300°, the aromatic nucleus is, 
little by little, broken up, and particularly in the case of benzene the 
reaction: 

CeHe + 9H,~6CH, 

methane 

tends to become more and more important.^^ 

363. When a compoimd can add several molecules of hydrogen in 
succession, we can sometimes contrive, by suitably choosing the tem- 
peratures, to produce one after the other of the various combina- 
tions.^' In the hydrogenation of anthracene over nickel, at 180°, 
perhydro-anthracene, C14H24, is obtained along with the dodeca- 
hydro-, at 200°, the octohydro-, and at 260°, the tetahydro- 
anthracene.^* 

364. The easy hydrogenations are those which take place over a 
wide range of temperatiu*e8, as the saturation of ethylene bonds or 
the reduction of nitro compoimds. The more difficult cases are those 

^* Sabatqbb and Mubat, Ann. de Chxm, (9), 4« 255 (1915). 

^* Sabatibb and Sbndbbbns, Ann, Chim. PhyB. (8), 4* 334 (1905). 

^" Sabatibb and Mah^hb, CompL rend., 137, 240 (1903). 

^« CiODCHOT, Ann. Chim. Phys. (8), ia» 468 (1907). 



366 CATALYSIS IN ORGANIC CHEMISTRY 134 

where the possible temperature interval is narrow, as is the case in 
the hydrogenation of the aromatic nucleus, especially with diphenols, 
pyrogallol/^ benzoic esters, and quinoline.^® 

365. As has been stated above (167), the hydrogenating activity of 
nickel is attributed to the rapid formation of a hydride formed 
directly by the hydrogen gas on the surface of the metal. This 
hydride is readily dissociated, and if it is brought into contact with 
substances capable of taking up hydrogen, it gives it to them very 
rapidly, regenerating the metal which can again form the hydride, 
repeating these reactions indefinitely. 

The well-attested impossibility of carrying on all sorts of hydro- 
genations with any sort of nickel leads to the idea that there are 
several stages of combination with hydrogen. The nickel produced 
above 700^ can doubtless form only the first hydride, comparable to 
that formed by copper, and capable of reacting with nitro groups or 
with an ethylene hydrocarbon. Only powerful nickel, such as is 
furnished by the reduction at a low temperature of the oicide pre- 
pared from the nitrate, can form a perhydride capable of hydro- 
generating the aromatic nucleus (167). 

RESULTS OBTAINED BY HYDROGENATION OVER 

NICKEL IN GASEOUS SYSTEM 

366. The results obtained by hydrogenation over reduced nickel 
can be divided into four groups: 

1. Simple reductions without fixation of hydrogen, 

2. Reductions with simultaneous fixation of hydrogen, 

3. Addition of hydrogen to molecules which contain multiple bonds 
between various atoms, 

4. Hydrogenations accompanied by decomposition of the 
molecule. 

REDUCTIONS EFFECTED WITHOUT FIXATION 

OF HYDROGEN 

367. The reduction effected by the aid of nickel corresponds most 
frequently to the elimination of oxygen in the form of water; it can 
also remove sulphur as hydrogen sulphide. 

368. Nitrous Oxide. The first case is furnished by nitrous oxide 
which is reduced to nitrogen, even at the ordinary temperature, with- 

^7 Sabatibb, BerichU, 44, 1907 (1911). 

" Sabatob and Mubat, Compt. rend., i$8, 309 (1914). 



135 HYDRCXIENATIONS 370 

out any production of ammonia or hydrazine. By increasing the 
•proportion of nitrous oxide in the hydrogen, the heat evolved raises 
the first portions of the nickel to incandescence, and there results a 
partial decomposition of the nitrous oxide with the appearance of red 
nitrogen peroxide, the hydrogenation of which carried on by the 
neighboring hot nickel gives a little anmionia.^* 

369. Aromatic Alcohols. The hydrogenation of aromatic al- 
. cohols over nickel at 350-400^ replaces the hydroxyl group by hydro- 
gen and leads to the corresponding aromatic hydrocarbon.'^ 

Benzyl alcohol is changed to toluene, phenylethyl alcohol to ethyl" 
benzene, benzhydrol, CeHa.CH(OH).CeHs, is changed quantitatively 
into diphenyl-methane, CeHa.CH^.CeHs, and phenyl-p.cresyl carbinol, 
into phenyl^. cresyl'tnethane. 

Likewise, vapors of triphenyl carbinol, carried along by benzene 
vapors and hydrogen over nickol at 400^, readily yield triphenyU 
methane. 

This reaction is particularly easy when the alcoholic hydroxyl is 
attached to a carbon atom adjoining a carbon atom united to hydro- 
gen in the same parafi^e side-chain. The mechanism of the reaction 
may then correspond to a dehydration into the phenyl-ethylene 
hydrocarbon, which is at once hydrogenated into the saturated hydro- 
carbon. Thus tolyl'dimethyl carbinol, CH3.CeH4.C(0H).(CH,)„ 
which is very readily dehydrated, gives with a nickel only slightly 
active cymene, which may be transformed into menthane if an active 
nickel is used below 180°." 

370. Phenols and Polyphenols above 250°. Phenol hydro- 
genated at 250 to 300° over nickel, gives only benzene with the elimi- 
nation of water: 

CeH,.OH + H, — HaO + CeH.. 

But the reaction is slow and much of the phenol passes by 
imchanged. If the attempt is made to hasten the reaction by 
raising the temperature, the benzene is attacked with the formation 
of methane. The three cresoles behave the same way and yield 
toluene. 

At 250° the diphenola (pyrocatechin, resorcine, and hydroquinone) 
undergo a similar reaction, the hydroxyl groups being successively re- 
placed by hydrogen, phenol being first formed and then benzene.*' 

^* Sabatisb and Sindbbbnb, Compt, rend,, 135, 278 (1902). 

*o Sabatbb and Murat, Ann, de Chim. (9), 4, 258 (1915). 

*^ Smoinof, J. RuB8ian Phys, Chem. Sac., 41, 1374 (1909). 

** Sabatbb and BmnoBMSB, Ann. Chim. Phys. (8), 4, 429 (1905). 



371 CATALYSIS IN ORGANIC CHEMISTRY 136 

371. Furfuryl Alcohol. This alcohol submitted to a careful 
hydrogenation over nickel at 190®, yields methylfurfurane.^* 

CH-CH CH-CH 

CH C.CH,OH -► CH C.CH, 

\/ \/ 

O O 

372. Carbon Disulphide. Carbon disulphide submitted to hydro- 
genation over nickel below 200®, gives an addition product having a 
very disagreeable odor (492), but if the operation is carried on at 
450-^00®, in excess of hydrogen, the reaction takes place thus: 

CS^ + 2H, — 2HaS + C. 

This reaction is utilized in freeing coal gas from carbon disulphide 
which it contains up to 0.02%. 

The gas is freed from hydrogen sulphide by chemical purification 
in the Laming absorbers and is then heated to 400® and passed 
through steel tubes 7 cm. in diameter containing porous earth im- 
pregnated with nickel and heated to between 400 and 500®. The gas 
is cooled when it passes out of the tubes and is freed by a second 
passage through the chemical absorbers from the hydrogen sulphide 
which has been formed. On account of the deposition of carbon and 
also on accoimt of a certain sulphurization of the surface, the nickel 
loses its activity rather rapidly. It is regenerated by passing air 
which burns up the carbon and converts the nickel to the oxide which 
is again reduced by the first portions of gas that enter. The installa- 
tion of this process at the Greenwich gas works is capable of handling 
500,000 cu. m. per day." 



REDUCTIONS WITH SIMULTANEOUS FIXATION 

OP HYDROGEN 

373. These reductions can be considered as true substitutions of 
hydrogen either for oxygen or, in a few cases, for the halogens, 
chlorine or bromine. 

374. Oxides of Nitrogen. Although the oxides of nitrogen are 
outside of the scope of this treatise, yet their close connection with 
organic nitro and nitroso compounds justifies us in mentioning the 
conditions of their catalytic hydrogenation. 

" Padoa and Ponti, lAncei, 15 (2), 610 (1909); C, 1907 (1), 670. 
^* Cabfbntib, J. Ga8 Lighting, xa6, 928 (1914). Evans, J. Sac, Ckem, Ind^ 
34, 9 (1915). 



137 I HYDROGENATIONS 377 

Nitric oxide, niO, is readily reduced above 180^ with the forma- 
tion of ammonia ^d water according to the equation: 

NO + 6H = NH3 + H,0. 

But the nitr^ oxide reacts with the ammonia more and more 
rapidly the higUer the temperatiu'e, giving nitrogen and water ac- 
cording to the equation: 

2NH3 + 3N0 — 6N + SELfi. 

By progressively increasing the proportion of nitric oxide, the 
metal becomes incandescent and this greatly increases the produc- 
tion of nitrogen.*' 

375. If hydrogen which has passed through a thin layer of liquid 
nOrogen peroxide, cooled a little below 0^, is passed over cold reduced 
nickel, a slight evolution of heat is noticed which is due to the 
formation of nickel nitride.** 

If it is heated to 180^, white fiunes of ammotdum nitrate and 
nitrite appear which, when hydrogenated further, give ammonia and 
water. We have finally: 

NO, + 7H — NH, + 2H,0. 

If the proportion of nitrogen peroxide in the hydrogai is increased 
by warming the vessel containing the nitrogen peroxide, the white 
fumes are produced in abimdance and incandescence of the nearest 
portion of the metal layer is noticed and a violent explosion soon 
takes place.*' 

376. The vapors of nitric acid mixed with hydrogen and passed 
over nickel at 290^ give much ammonium nitrate. At 350^ only 
water, ammonia, and free nitrogen are produced.*' 

377. Aliphatic Nitre Compounds. Nitromethane is completely 
hydrogenated between 150 and 180^ to methyUamine without any 
side reactions. But above 200^ and particularly towards 300^, there 
is partial hydrogenation of the methyl-amine into methane and 
ammonia:*^ 

CH3 . NO, + 4H, — CH, + NH, + 2H,0 

and at the same time, the formation of certain amounts of dimethyl- 
and trimethyl-amines along with the ammonia by a reaction identical 
with that which has been described in the hydrogenation of nitriles. 

*' Sabatub and Sbndisbnb, Compt. rend., 135, 278 (1002). 

*« Sabatbb and Bbnudoins, Ann. Chim. Phys. (7), 7, 413 (1895). 

*^ Sabatib and Qssiobmss, Compt. rend., 135, 226 (1002). 



378 CATALYSIS IN ORGANIC CHEMISTRY 138 

Likewise mtroethane is readily transformed at 200° into ethyU 
amine accompanied by diethyl^amine, triethyUamine and ammonia. 
At 350° the matter is complicated by the formation of ethane and also 
of methane which is due to the dissociation of the ethane by the 
nickel. But this secondary formation of the hydrocarbon is less 
than with nitromethane. 

378. Aromatic Nitre Compounds. Above 200° nitroheTizene is 
rapidly transformed into amline, but the aniline is immediately hydro- 
genated to form cyclohexylamine, etc. (466) . If only slightly active 
nickel is used, the nucleus is not hydrogenated and aniline is the only 
product.'* 

Above 250°, a part of the nitrobenzene is reduced to benzene and 
ammonia : 

CeH. . NO, + 4H, = CeHe + NH3 + 2H,0. 

This reaction is more in evidence above 300° and even the benzene 
is broken up to form methane: 

CeH, . NO, + 13H, — 6CH4 + NH3 + 2H,0. 

Ortho and msta nitrotolitenes behave similarly with a nickel cat- 
alyst at 200 to 250°, and as the further hydrogenation of the resulting 
toluidines does not take place readily, the toluidines are obtained 
nearly pure. 

These reactions can be used in the factory and it has been pro- 
posed to prepare aniline by passing a current of hydrogen and steam 
through nitrobenzene maintained at 120° and then into a long tube 
containing reduced nickel also kept at 120°. A theoretical yield is 
claimed." 

379. a-Nitronaphthalene gives at 300° beautiful white needles of 
a-naphthyl amine, but if the temperature is raised to 330°, or better, 
to 380°, ammonia is evolved and there condense, along with the 
diminishing naphthyl amine, naphthalene and tetrahydronaphtha- 
lene?^ We have: 

CioH, . NO, + 4H, — C10H3 + NH, + 2H,0. 

380. Dinitro derivatives are transformed with the same facility. 
The dinitrobenzenes give the corresponding diamines at 190-210°. 
At 250°, there is the splitting off of ammonia to form aniline.*® Like- 

<^ Sabatzeb and Sbndsrbnb, Compt. rend., 135, 226 (1902). 

** Fasbw. MmsTEB, Lucius and BstNiNa, Oerman patent, 282,492 (1913). 

w MiONONAC, BuU, Soc. Chim. (4), 7, 164 (1910). 



139 HYDROGENATIONS 383 

wise the dimtrotoluenes yield the cresyMiamines at 175-180®, but 
above 190® ammonia is split off and the toluidines are the chief 
products.*^ 

381. The nitrophenols hydrogenated over nickel at 160-190®, yield 
the amino-phenols regularly; but there are simultaneously produced 
certain amounts of ammonia and phenol and also a little aniline.*' 

382. Esters of Nitrous Acid. It is stated in all the textbooks 
that a fundamental distinction between the nitrohydrocarbons and 
their isomers, the nitrites, is that the nitro compounds yield amines 
on hydrogenation, while the nitrous esters are either not affected or 
give the alcohols and ammonia without any amine. 

Gaudion has found that nitrous esters are regularly hydrogenated 
by nickel to give amines exactly like their isomers. This author has 
worked at 180® with methyl and ethyl nitrites, at 200® with propyl 
and isopropyl, and at 220® with iaohutyl and isoamyl. 

As a consequence of the secondary reaction already mentioned, 
all three amines, primary, secondary, and tertiary, are obtained, the 
secondary always in the largest quantity. Thus from isoamyl nitrite, 
31% mono-, 62% di-, and 7% tri-isoamyl-amines are obtained. 

The discussion of these facts has led Gaudion to assume that there 
is an isomerization of the nitrous esters into the nitro bodies at the 
temperature of the reaction.'* 

The reality of this transformation by heat alone has since been 
established. It begins at 100® and is rapid at 125-130®.*^ 

By carrying on the hydrogenation at low temperatures, around 
125-130®, over nickeled asbestos, the unchanged nitrous esters are 
hydrogenated along with the nitro bodies into which they are partly 
isomerized so that there is simultaneous production of ammonia and 
the corresponding alcohol from the nitrite and of the amine from the 
nitro compound; while when a nitro compound is hydrogenated, the 
primary amine alone is formed without any secondary or tertiary. 
This is the case with nhethyl, ethyl, propyl, isobutyl and isoamyl m- 
trites,^^ 

383. Oximes. In the aliphatic series, aldoximes and ketoximes 
are readily reduced by hydrogen in the presence of nickel at 180- 
220® to give primary and secondary amines with a small amount of 
tertiary. 

With acetoxims, the chief product is diethyl amine, while with 

«i MiONONAC, BuU. Soc. Chim. (4), 7, 823 (1910). 
" MiONONAC, BuU, Soc. Chim. (4), 7, 270 (1910). 
»« Gaudion, Ann4 Chim, Phya. (8), 25, 129 (1912). 
*^ Nbooi and Chowbubg, /. Chem, Soc, zog, 701 (1916). 
** Naooi and CHOWDUBa, /. Chem. Soc, ziz, 899 (1917). 



384 CATALYSIS IN ORGANIC CHEMISTRY 140 

heptcddoxime, CeH^, . OH : N . OH, the primary amine is the most 
abundant. 

The axime of acetone gives isopropylramine, with twice as much 
of the di- and a little of the tri-isopropyl-amine. Analogous results 
are obtained with biUanoxime(2)y C2H5(CH8)C : N.OH, pentaru- 
oxiine(2), pentanoxime(3) , and 2f4L'dimethyl pentanoxifne(3) .^ 

By this means the secondary amines from secondary alcohols can 
be prepared with good yields, a class of substances otherwise difficult 
to obtain. 

384. This method can also be applied to aromatic aldoximes in 
spite of the difficulty of vaporizing them without decomposition. It 
is best to operate with a rapid current of hydrogen and at as low a 
temperature as possible. Acetophenone-oxime, CeH^ . C ( : NOH) .- 
CH3, carried thus over nickel at 250-270^, ^ves a small amount of 
the primary amine, CeHs.CHCNHg) .CH,, a larger amount of the 
secondary amine and some acetophenone regenerated by the action of 
the resulting water on the oxime. 

The results are not so good with propiophenone-oxime, from which 
small amounts of the primary and secondary amines are obtained 
along with much phenylpropylene and phenylpropane, and still poorer 
results are obtained with hutyrophenone oxime. 

On the contrary, the method serves well with henzophemme-oxima 
from which up to 70% of the primary amine, (CeHB),CH.NH2, is 
obtained with a certain amount of the secondary.'^ 

385. The hetoximes of the cydoparafflnes react in an analogous 
manner. 

The hydrogenation of cyclohexanone-oxime over nickel at 190- 
200** gives cyclohexyl-amine regularly with a little dicyclohexyl 
amine and aniline.*^ The results are not so good with the three 
methyl-cyclohexanone-oximes, as the yields of the amines are poor. 

CHj.CHjv 
The hydrogenation of cyclopentanone-oximSf • ^C : NOH, 

CHj.CH,/ 

over nickel at 180^, proceeds smoothly to give a mixture of the three 
cyclopentyl-amines, the secondary forming half of the product and 
the primary and tertiary, each about one-fourth. Analogous results 
are obtained with methyl-cydopentanone-oxmie.^^ 

>« Mau^hs, CompL rend., Z40, 1691 (1905), Ibid., 141, 115 (1905) and BuIL 
80c. Ckim. (4), 15, 327 (1914). 

*T Mau^hb and Mubat, BuU. 3oc. Chim. (4), 9, 464 (1911). 

•P Amoboux, BuU. Sac. Chim. (4), 9, 214 (1911). 

*' Sabatikb and Maujob, Compt. rend., is^$ 985 (1914). 



141 HYDROGENATIONS 888 

Menthone-oxime yields the primary and secondary amines and a 
little regenerated menthone.^ 

Cafnphoroxime, when hydrogenated over nickel ^ves the corre- 
sponding amine in good yield.^ 

386. Aliphatic Amides. Acetamide is readily hydrogenated at 
230^ by nickel with the production of water and ethylamine and also 
some dimethylamme, due to the decomposition of the primary amine 
by the metal, and a small amount of ammonia. 

Propionamide, CH, . CH, . CO . NH,, gives results entirely sinii- 
lar.« y^ 

387. Ethyl Acetoacetate. Ethyl acetoacetate, the ester of an 
unstable j3-keto-acid, gives, when hydrogenated over nickel, a triple 
reaction: *■ 

1. A hydrogenation by substitution: 

CM3 . CO . CM2 . CO2 • C2M5 — > CM3 . CH2 • CH2 . CO2 . C2M3. 

ethyl butyrate 

2. A breaking up of the molecule into the fragments CH, . CO .- 
CH2- and -CO2 . CjHs which are hydrogenated separately, liie first 
into acetone and then iaopropyl alcohol (435), the second into ethyl 
formate which is decomposed, under the reaction conditions, into 
ethyl alcohol and carbon monoxide which may go into methane (867) . 

3. A condensation of the molecule with the formation of solid 
dehydroacetic add, (CH, . CO) «, which is produced by the action of 
heat alone on ethyl acetoacetate,^ and which the presence of the 
nickel, without the hydrogen, causes to be formed at 250^ : 

2 CH, . CO . CH2 . CO2 . C2H, — (CH2C0)4 + 2C2H, . OH. 

388. Aromatic Aldehydes. Contrary to what takes place with 
aliphatic aldehydes, the hydrogenation of aromatic aldehydes over 
nickel does not reduce them to alcohols, but tends to replace the oxy- 
gen by hydrogen, H,, to give the aromatic hydrocarbons, which below 
260^ may be more or less hydrogenated to the cyclohexane hydro- 
carbons. There is, at the same time, some decomposition of the alde- 
hyde into the hydrocarbon and carbon monoxide (618). Thus 
between 210 and 235^, benzaldehyde gives toluene and benzene 
according to the two reactions: 

C.H5 . CHO + 2H2 — H2O + CeH. . CH, 
C,H, . CHO — CO + CeHe, 

^ MiOLHB and Mubat, BtiU. 80c. Chim. (4), 9, 464 (1911). 
«^ Alot and Bbustob, BuU. Soc. Chim. (4), 9, 734 (1911). 
«s Mauab, BvU. Soc, Chim. (3), 35» 614 (1906). 
«• Sabatibb and Mau^hb, Bidl. Soc. CMm. (4), 3, 232 (1908). 
M Gbutbbb, ZeU. /. Chem., a, 8 (1886). 



389 CATALYSIS IN ORGANIC CHEMISTRY 142 

and these are accompanied by certain proportions of methylcyclo- 
hexane and cyclohexane, the carbon monoxide being partly reduced 
to methane (393) ." 

389. Aromatic Ketones. The hydrogenation of aryl-aliphatic 
ketones, effected rapidly over a nickel of only moderate activity or 
at a temperature above 250^, is limited to replacing the ketone 
oxygen by H, with the production of the corresponding aromatic 
hydrocarbon. Thus acetophenone, CeHg . CO . CHj, gives ethylr- 
benzene, CeHj . C2H5 ; methyl-p.cresyl ketone, CH, . CeH4 . CO .- 
CHg, yields p.methyl^^thyl benzene; p.tert-butyl-acetophenone, 
(CH8)8C . CgH^ . CO . CHg, gives p.ethylr-tert-butyl-bemene; and 
benzyl-acetone, CeHg . CH, . CHj . CO . CHg, yields butyl-benzene.^* 

But when the hydrogenation is carried on at 180^, with an active 
nickel which is capable of hydrogenating the nucleus, the aromatic 
hydrocarbon is reduced to the cyclohexane derivative. One can be 
sure of avoiding this complication if nickel is used that has been so 
altered that it can not hydrogenate benzene or if the operation is 
carried on about 300°, the temperature at which cyclohexane deriva- 
tives are dehydrogenated even in excess of hydrogen.*^ 

It is the same way with diaryl ketones which are quantitatively 
reduced to the corresponding hydrocarbons by nickel at 300°. 

Thus benzophenone at 300° is entirely reduced to diphenylmethane, 
while with an active nickel at 160°, dicyclohexylmethane is formed. 

Desoxybenzoine, CgHg . CH, . CO . CeHg, yields dibenzyl, C^Hg .- 
CH, . CH, . CgHg, at 350°. Likewise dibenzyl ketone, CgHg . CH, .- 
CO . CH, . CgHg, is 70% transformed at 400° into symmetrical 
diphenylpropane, which is accompanied by toluene formed by the 
breaking up of the molecule with the separation of carbon monoxide 
which is reduced to methane. The same hydrocarbon is formed by 
the hydrogenation over nickel at 350° of phenyl-phenylethyl ketone, 
CgHg . CO . CH, . CH, . CgHg. *® 

390. Likewise methylorftaphthyl-ketone yields a-ethylnaphtha-- 
lene, and methyl'^-naphthyl and the propyl-naphthyl ketones behave 
in a similar manner.** 

Hexahydroanthrone is hydrogenated at 200° into octohydroanthra- 
cene: '^ 

« Sabatier and Sbndbrbns, CompL rend,, 137, 301 (1903). 
*« Darzbns, CompL rend,, 139, 868 (1904). 
*T Sabatier and Murat, Ann, Chim. (9), 4, 263 (1916). 
*« Sabatier and Murat, Ann, Chim, (9), 4, 284 (1915). 
« Darzbns and Rost, CompL rend,, 146, 933 (1908). 
»» Gk)DCH0T, BuU. 80c. Chim. (4), i, 712 (1907). 



143 HYDROGENATIONS 392 

yCHjv yCH2V^ 

\C0 / \CH,/ 

Likewise methyl (l)cyclopentanone(S) is advantageously trans- 
formed at 250^ into methylcyclopentane^^ 

^^-CO— x 
Dihydrocamphorone, CHs.CH; ;CH.CH(CH8)2, is hy- 

NCHj.CH,/ 

drogenated at 180^ to form methyl-isopropyl-cyclopentane, boiling at 
132*^." 

391. Aromatic Diketones. Similarly to the monoketones, the 
aromatic diketones, when hydrogenated over nickel, give the hydro- 
carbons."' 

Dibemoyl, CeHj . CO . CO . C^Hg, which is an a diketone, is hydro- 
genated over nickel at 220° to symmetrical diphenylethane, or di- 
benzyl, CeHg . CHg . CH, . CeHg, beautiful crystal flakes, without 
appreciable secondary reactions. 

Benzoine, CeH, .CH(OH) .CO.CeHg, gives the same hydro- 
carbon as the sole product at 210-220°. 

Benzoyl-acetone, CJB.^ . CO . CH, . CO . CH,, which is a j8 dike- 
tone, when hydrogenated over nickel at 200°, reacts in two ways: 

1. Butylbenzene is formed to an extent of about 80%. 

2. Following a general tendency of j3 diketones, there is a break- 
ing up into two fragments, CeHj . CO- and -CHj . CO . CHj, which 
f re hydrogenated separately, the one into toluene and the other into 
acetone, and then into isopropyl alcohol. 

392. Anhydrides of Dibasic Acids. The anhydrides of dibasic 
acids which have been submitted to hydrogenation at low tempera- 
tures, have given only the corresponding lactones. 

Stxcmic anhydride gave butyrolactone: "* 

CHj.COv. CHa.CHjv 

CH,.CO/ CHj.CO/ 

Over nickel at 200°, phthalic anhydride yields phthalid quantita- 
tively: 

/COk /^^«\^ 

\co/ \co/ 

Bi Zblinskt, Berichte, 44, 2781 (1911). 
" GoDCHOT and Taboust, Compt, rend., 156, 470 (1913). 
BS Sabatub and Mmlbm, Compt. rend^ 145, 1126 (19(y7). 
s« EuKMANN, Chem. Weekblad, ^ 191 (1907). 



393 CATALYSIS IN ORGANIC CHEMISTRY 144 

Even by operating at 130^ with very active nickel it is impossible 
to replace the second carbonyl."* 

In the same manner camphoric anhydride is changed into campho' 
lid exclusively: ** 

393. Carbon Monoxide. The direct hydrogenation of carbon 
monoxide over nickel gives a simple method for the synthesis of 
methane: 

CO + 3H, — H,0 + CH4. 

The reaction commences aromid 180-200^ and goes on rapidly 
without complications at 230-250^. With the theoretical mixture of 
hydrogen and carbon monoxide, 3:1, the reaction is practically com- 
plete, the resulting gas being nearly pure methane. 

The nickel is not sensibly altered by the reaction when it is car- 
ried on below 250^ and can be used indefinitely. On cooling it is 
found to be slightly carbonized but still pyrophoric and completely 
soluble in dilute hydrochloric acid without carbonaceous residue. 

The reaction is less complete when the carbon monoxide is in ex- 
cess ; in an experiment carried out with 85 volumes of carbon mon- 
oxide to 51 volumes of hydrogen, almost one third of the hydrogen 
passed through the tube without combining, although the velocity of 
the gas was no greater than in the experiment quoted above. 

394. If the operation is carried on above 250^, complications arise 
due to the special effect that finely divided nickel has on carbon mon- 
oxide which it breaks up into carbon and carbon dioxide (614) : 

2C0 — C + CO,. 

The carbon dioxide which is thus formed is partially hydrogenated. 
Its proportion is greater, the higher the temperature, since the 
secondary reaction which produces it is greatly accelerated by rise 
of temperatiure. 

Thus when operating at 380^ with the theoretical mixture which 
gives methane completely at 250^, a gas is obtained which contains: 

Carbon dioxide 10.5% by vol. 

Methane 67.9 

Hydrogen 21.6 

B« EuKMANN, Chem, Weekblad, 4, 191 (1907). 
" GoDCHOT, BuU, 80c, Chim. (4), i, 243 (1907). 



145 HYDROGENATIONS 897 

At the same temperature, water gas, equal volumes of hydrogen 
and carbon monoxide, gives 62.6% carbon dioxide, 39.8% methane, 
and 7% hydrogen. 

When the percentagie of carbon monoxide is still further increased, 
the hydrogenation is greatly weakened; much hydrogen passes 
throu^ and the proportion of carbon dioxide becomes very large.** 

395. Carbon Dioxide. Like the monoxide, carbon dioxide is 
readily hydrogenated over nickel to form methane: 

CO, + 4H, — CH^ + 2H,0. 

The reaction be^ns at a higher temperature than that with car- 
bon monoxide, namely, around 230^, and is rapid above 300^ and 
does not offer any considerable complications up to 400^. The theory 
calls for four volumes of hydrogen to one of carbon dioxide. With 
gas mixtures containing a larger proportion of hydrogen, the carbon 
dioxide disappears almost completely. 

Thus in an experiment with 82% of hydrogen and 18% carbon 
dioxide, passed through the tube containing the nickel at the rate of 
55 cc. per minute, the issuing gas contained: 
With the nickel at 258^ 17.2% by vol. carbon dioxide 

" " " " 283** 0.5% " " " " 

396. Carried on at 300^ with an excess of hydrogen, this reaction 
gives a very advantageous method for preparing pure meihane if 
liquid air is available for' condensing the methane. The gas is washed 
with caustic potash to free it from traces of carbon dioxide, dried and 
the methane condensed, leaving the hydrogen as gas."^ 

397. Application to the Manufacture of Illuminating Gas. 
The production of methane by the direct hydrogenation of carbon 
dioxide over nickel can be used for the conunercial preparation of a 
gas rich in methane having a higji calorific power and capable of 
being used either for heating or for lighting by using incandescent 
mantles.*® 

If hydrogen is available (produced electrolytically or by the action 
of iron on steam at a red heat) , the hydrogenation of carbon dioxide 
over nickel at 300 to 400^ is an excellent way to prepare methane."* 

But the preparation of the hydrogen costs too much for it to be 
used for the manufacture of illuminating gas. One must start with 

^ Sabatqb and finnnsENS, Compt. rend^ 134, 514 (1002). 
*^ Sabactb and 8nn>iBBN8, Compt, rend., 134, 680 (1002). 
B* Babatiol, VI Internal, Cong, Pure and App, Ckem,, Rome, 1006, IV sect 
p. 188. 

•' Sabatub, French patent, 366,471, June 17, 1006. 



398 CATALYSIS IN ORGANIC CHEMISTRY 146 

a cheap commercial gas such as water gas, RichS gas, Siemens gas, 
etc. Various methods may be followed. 

398. First method. Water gas obtained by the action of steam 
on red-hot carbon varies in composition according to the temperature 
at which it is prepared. 

At a bright red, there are equal volumes of hydrogen and carbon 
monoxide: 

C + H,0 — CO + H,. 

At a lower temperature (a very dull red) there are only carbon 
dioxide and hydrogen: 

C + 2H,0 — CO, + 2H,. 

If the temperatiure is intermediate (cherry red), the reaction is 
intermediate: 

20 + 2H2O =- CO + CO, + 3H,. 

If in this case the carbon dioxide be removed by any method there 
remains the mixture CO + SH,. The carbon dioxide may be ab- 
sorbed by a solution of potassium carbonate which is changed to the 
bicarbonate, but is regenerated with evolution of carbon dioxide by 
boiling. The carbon dioxide may be solidified by refrigeration or 
absorbed in cold water under pressure. The residual mixture, 
CO + 3Hj, is converted into pure methane by passing over nickel 
at 230-250^, 5 volumes of water gas thus furnishing 1 volume of 
methane. A practical difficulty arises from the fact that the catalyst 
must be kept between 230 and 250°, since above 250® there is char- 
ring with loss of carbon and fouling of the nickel resulting in a rapid 
diminution of its catalytic power. 

399. Second Method. The operation is carried on in two phases: 
Water gas prepared at a hi^ temperature and very nearly 

CO + H2 is passed over nickel at 400 to 600°, by which all the carbon 
monoxide disappears forming either methane with the available hy- 
drogen, or splitting up into carbon dioxide (614) and finely divided 
carbon which is deposited on the nickel. If from the gas so produced, 
the carbon dioxide is absorbed, the remainder is very rich in methane. 
For the conditions cited above (394), the composition would be 83.8% 
methane and 15% hydrogen with a calorific power of 7,800 calories 
per cu. m., while the original gas had only 2,880. This is the gas of 
the first phase. 

If steam be passed over the intimate mixture of carbon and nickel 
obtained above, kept at 400 to 500°, the carbon reacts rapidly tend- 
ing to give hydrogen and carbon dioxide which being in the nascent 



147 HYDROQENATIONS 401 

state react to give a certain proportion of methane. The final product 
is a mixture of hydrogen, methane and carbon dioxide and if the car- 
bon dioxide is eliminated, there remains a mixture of hydrogen and 
methane of high calorific power which can be used. This is the gas 
of the second phase, less rich in methane than the first. Its formation 
has eliminated the carbon from the nickel which is then ready to 
repeat the first phase of the reaction.*^ 

400. Third Method. The gas of the second phase can be obtained 
alone by preparing at first the intimate mixture of nickel and carbon 
by the action of finely divided nickel on various gases rich in carbon 
monoxide such as Siemens gas or producer gas. The carbon mon- 
oxide disappears leaving carbon dioxide and carbon. It is sufficient 
to maintain this carbonaceous mass at 400 to 500^ and pass super- 
heated steam over it to have a mixture of methane, hydrogen and 
carbon dioxide which can be used after the latter is eliminated.^ 

401. Fourth Method. The two phases of the reaction that have 
just been described can be combined in practice. All that is required 
is to maintain finely divided nickel at 400 to 500° and pass over it a 
mixture of suitable proportions of water gas (or Rich£ gas^*) and 
superheated steam. Under these conditions the carbon monoxide dis- 
appears and is replaced by hydrogen, methane and carbon dioxide, 
and if the latter is eliminated, we have in one operation a usable 
mixture of hydrogen and methane. 

This method of operating appears economical. The amount of 
nickel required for the reaction is less than 1 k. for making 1 cu. m. 
of gas per hoiu*. Besides, if the carbonated gases introduced are suit- 
ably purified and if this purification is completed by passing over 
copper turnings heated to 600°, the nickel may be said to retain its 
catalytic power indefinitely. By starting with water gas a gas is 
obtained having an average composition of 48% methane and 52% 
hydrogen and having a calorific power of 5,800 calories per cu. m. 
This gas does not contain an appreciable amount of carbon monoxide 
which is present in coal gas in considerable amount (from 8 to 15%) 
and which renders it decidedly toxic. 

In fact the reactions that take place with these conditions under 
the influence of nickel between water gas and steam can be sunmied 
up in this equation: 

5 (CO + H,) + H^O — 2CH, + 2H^ + 3C0,. 

water gM 

•<» Sabatib, French patent, 355,900, July 5, 1905. 
*^ Sabatdb, French patent, 355,900, 1905. 

*^ The Rich^ gas is a mixture of caibon monoxide, hydrogen, methane and 
carbon dioxide prepared by heating woody or cellulose materials. 



402 CATALYSIS IN ORGANIC CHEMISTRY 148 

Theoretically 5 volumes of perfect water gas should ^ve 2 volumes 
of the mixture containing 50% methane. In practice, as the water 
gas contains some carbon dioxide, about 3 volumes are required on 
the average for 1 volume of the finished gas. 

402. The use of industrial refrigeration permits a very advan- 
tageous modification of the first process (398) . The water gas should 
be prepared at the highest possible temperature so as to contain 
CO -f H, and a little carbon dioxide and nitrogen. By suitable re- 
frigeration 75% of the carbon monoxide can be liquefied and a mix- 
ture of CO + 4H2 obtained which passing over nickel at 200 to 250^ 
would furnish e^ctly the gas CH^ + H, equivalent to coal gas. The 
refrigeration condenses all of the substances that may be toxic to the 
nickel (sulphurous gases, etc.) and hence guarantees the long life of 
the catalyst. 

The carbon monoxide separated by the liquefaction may be used 
for heating the catalyzers or for driving motors.^® 

403. Aromatic Halogen Derivatives. The direct reduction of 
aromatic halogen derivatives by hydrogen in the presence of nickel 
may take place more or less readily : it is easy with chlorine deriva- 
tives, less easy for bromine derivatives, and difficult lor iodine com- 
pounds; the reason being easy to find in the decreasing affinity of the 
halogens for hydrogen as we pass from chlorine to iodine, since the 
simultaneous formation of the hydro-acid determines the substitution 
of hydrogen. 

When the vapors of chlorbenzene are carried by hydrogen over 
reduced nickel at 160^, a strong absorption of hydrogen is noted at 
once and a little cyclohexane is condensed without any chhrcyclO" 
hexane. The chlorine remains, fixed by the nickel, the surface of 
which loses all activity by being changed to the chloride. After a 
short time the chlorbenzene passes through unchanged. 

But if the temperature is raised above 270^ a vigorous evolution 
of hydrochloric acid is observed and a readily separated mixture of 
benzene and chlorbenzene is condensed. At the same time there is 
the formation of crystals of diphenyl. 

In contact with nickel at 270^ or above, chlorbenzene gives nickel 
chloride, and the liberated residue, C^Hs-, combines with hydrogen 
to give benzene and unites with itself to form a small amount of 
diphenyl. But at this temperature the nickel chloride is reduced by 
hydrogen forming hydrochloric acid and regenerating the nickel which 
repeats the reaction indefinitely. 

404. An analogous reduction is observed when the polychlor- 

** Sabathh, Second Congress on Refrigeration, x» 115 (1912). 



149 HYDROGENATIONS 406 

derivatives of benzene are acted on by hydrogen in the presence of 
nickel above 270°; the chlorine atoms are progressively replaced by 
hydrogen. 

Thus m.dichlorbemene gives a mixture containing: 

Benzene 30% 

Monochiorbenzene 60% 

Unchanged dichlorbenzene 10% 

pjyichlorbenzene ^ves 35% benzene and 66% monochiorbenzene. 

Perchlarbemene, Cede, acts in the same way at 270° and ^ves 
a mixture of the trichlorbemenes (particularly the 1,2,4), dichlor-' 
benzenes, monochiorbenzene, and benzene. 

The presence of aliphatic side-chains and hydroxyl groups facili- 
tates the reduction, the chlortoluenes being more readily reduced than 
chlorbenzene. 

2,^fi-Trichlorjj^ienol is readily reduced at 270° and ^ves 70% 
of phenol accompanied by monochlorphenols, particularly the artho. 

The reduction goes even better with amino derivatives, such as 
the chloramlines which give aniline hydrochloride at 270°. 

The chlamitrobemenes suffer simultaneous reduction of the nitro 
group and elimination of the chlorine, furnishing aniline hydrochloride 
at 270°.** 

405. It can be foreseen that the reduction of bromine derivatives 
will be more difficult, since the temporary nickel bromide is less 
easily reduced by hydrogen. However, the reaction can be carried 
out well with monobrombemene at 270° and also with p.bromtoluene, 
the bromanUines and the bromnitrobemenes. 

2fifi~Tribromphenol readily yields phenol accompanied by 
p.bromphenol and 2y4Hltbroinphenol. 

406. The difficulties are greater for the iodine derivatives. lodo- 
benzene pasi^ over nickel with hydrogen at 270° ^ves no lasting 
evolution of hydriodic acid; some benzene and diphenyl are formed, 
but the reaction stops, since the nickel is not restored by the hydrogen 
and does not continue the reaction. 

If pure hydrogen is passed into the tube, fumes of hydriodic acid 
appear, hence nickel iodide is reduced by hydrogen at 270° but not 
in the presence of iodobenzene, doubtless because this compound 
gives iodine to the nickel faster than the hydrogen can remove it. 
Practically, tiie reduction of iodobenzene can be forced by alternately 
passing pure hydrogen and hydrogen mixed with iodobenzene vapors 

M Sabatikb and Mau^hz, Compt rend., 138, 245 (1904). 



407 CATALYSIS IN ORGANIC CHEMISTRY 150 

over the nickel at 270^. But under these conditions the metal is not 
a true catalyst.*" 

407. Esters of Halogenated Aliphatic Acids. Vapors of ethyl 
mono-, di-y and tri-chloracetates, when passed over nickel at 300^, 
with excess of hydrogen, are reduced to ethyl acetate, the chlorine 
atoms being successively replaced by hydrogen. Ethyl bromacetate 
is as readily reduced to ethyl acetate.*^ 

^B Sabatieb and Mah^hb, Compt. rend., 138, 245 (1904). 
** SiffiATiBB and MaH/Hb, Compt, rend., 269, 758 (1919). 



CHAPTER IX 

HYDROGENATIONS (Continued) 

HYDROGENATIONS IN THE GAS PHASE — USE 

OF NICKEL (Continued) 

ADDITION OF HYDROGEN 

408. Many hydrogqnations correspond to the fixation of hydrogen 
by addition. This addition takes place either to free carbon, whi(j};i 
is rare, or to complex molecules containing double or triple bonds 
between the atoms. We will examine these in the following order: 

1. Direct fixation by carbon, 

2. On double bond between two carbon atoms, so-called ethylene 
bond, C : C, 

3. On triple bond between two carbon atoms, called the acetylene 
bond, C : C, 

4. Triple bond between carbon and nitrogen, C : N, 

5. Quadruple bond between carbon and nitrogen, C j N, 

6. Double bond between carbon and an oxygen atom, C : 0, 

7. Aromatic nucleus, 

8. Various rings, 

9. Carbon disulphide. 

z. Direct Fixation of Hydrogen by Carbon 

409. Berthelot noted' the direct union of hydrogen and carbon at 
the temperature of the electric arc^ to form acetylene which was 
necessarily accompanied by some methane and ethane resulting from 
the pyrogenetic decomposition of the acetylene. 

Bone and Jerdan state that carbon unites directly with hydrogen 
at 1200'' forming 1 to 2% methane.^ 

But Berthelot, carrying out the reaction with pure carbon in a 
quartz tube, could not confirm the formation of methane and con- 
cluded that it must have come from impurities in the carbon used by 
the English chemists.' 

^ Bbbthslot, Ann, Chim. Phys, (4), 13, 143 (1868). 
* BoNB add Jma)AN, J. Chem, 80c., 71, 42 (1897). 
s Bbthslot, Ann. Chim. Phyi (8), 6, 183 (1905). 

161 



410 CATALYSIS IN ORGANIC CHEMISTRY 152 

410. According to Henseling, the formation of methane by carbon 
and hydrogen begins at 300° in the presence of finely divided nickel. 

Sabatier and Senderens, by passing hydrogen at 250° over the 
intimate mixture of carbon and nickel which is formed by the action 
of reduced nickel on carbon monoxide between 250 and 300°, have 
definitely proved the production of methane, but also detected water 
vapor. After some time the formation of methane ceased though 
there was still much carbon with the metal. They attributed the 
formation of methane and water to the presence of a nickel carbonyl 
combination formed by the action of the carbon monoxide. The 
same chemists found no methane when the carbonaceous mixture had 
been prepared above 400°, a temperature at which carbonyl com- 
pounds can not exist.^ 

411. Mayer and Altmayer have confirmed the very slow fonnation 
of methane from carbon in contact with nickel or cobalt. At all tem- 
peratures above 260° methane is decomposed by nickel into carbon 
and hydrogen, the amount remaining being fixed for each tempera- 
ture, and the same whether the limit be approached from above or 
from below as is true with all reversible reactions (19), and not al- 
tered when cobalt is substituted for nickel. The amounts of methane 
at equilibrium are: 

At 250° 98.8% by volume 

536° 515% 

625° 24.7% 

850° 1.6% 

But this formation is very slow and could never be used for the 
preparation of methane. The velocities of the mixtures of gases 
passed over the mixture of carbon and nickel to obtain the equilibrium 
were not over 02 to 0.3 cc. per minute.* 

2. Ethylene Double Bond 

412. The ethylene double bond is very easily attacked by direct 
hydrogenation over nickel and adds two atoms of hydrogen. This is 
readily accomplished by nickel reduced above 500° and even by nickel 
which has been weakened by the action of poisons. 

413. Hydrocarbons. Ethylene is hydrogenated by nickel from 
30° up, the reaction which continues indefinitely, with evolution of 
heat, gives ethane exclusively. The hydrogenation is more rapid 
toward 130-150°.« 

^ Sabatub and OmtnasBaauB, Bidl. 8oc, Chim, (4), z, 107 (1907). 

* Mates and AuTMATSBy Berichte, 40, 2134 (1907). 

* Sabatibb and Sbndbons, Compt. rend., 124^ 1369 (1897). 



153 HYDROGENATIONS IN THE GAS PHASE 414 

In the presence of excess of hydrogen, all the ethylene disappearsi 
while with excess of ethylene all the hydrogen is us^ up and a mix- 
ture of ethane and ethylene is obtained from which it is easy to re- 
move the latter by bromine water leaving the ethane pure. 

This reaction has been used for the manufacture of ethane for 
refrigerating machines. The mixture of equal volumes of ethylene 
and hydrogen is passed through tubes 1 m. long and 7.5 cm. in diam- 
eter containing reduced nickel and heated to 200^. With a velocity 
of 2 cu. m. per hour a gas containing 80% of ethane is obtained. In 
order to complete the union of hydrogen and ethylene the mixture 
is compressed to 30 or 40 atmospheres in a vessel filled with nickeled 
pumice.^ 

Above 300° nickel decomposes ethylene (912) with the liberation 
of carbon, and the production of methane and certain amounts of 
higher paraffines which can be liquefied.* 

414. Other ethylene hydrocarbons can be transformed into the 
corresponding satiarated hydrocarbons below 160° without any com- 
plications. But above 200° and particularly above 300° there can be 
partial breaking of the carbon chain with the formation of saturated 
hydrocarbons with smaller numbers of carbon atoms and also more 
complicated. 

With propylene, CHf.CHiCHs, the reaction commences in the 
cold and up to 200° nothing but propane, CH, . CH, . CH,, is produced 
so long as the hydrogen is in slight excess. Whoi the propylene is in 
excess, particularly above 290°, small amoimts of higher liquid hydro- 
carbons with petroleum odors are formed, and at higher tonperattires 
there is more and more deposition of carbon with splitting up of the 
propane. 

TrimethyUethylene, or 2'fnethyUhiUylene, (CH.) ^C : CH . CH,, 
is totally hydrogenated by excess of hydrogen into pure 2'methyl' 
butane or isopentane, at 150°. 

Likewise hexene{2) gives hexane; and caprylene, or octene(l), 
octane without complications below 160°.' 

By the hydrogenation of 2^'dimethyl'methylene(3)'pentane, over 
nickel at 160°, 2^,Z'trimethyUpentane, boiling at 110.5° is obtained, 
and likewise 2fi'dimethyUheptane, boiling at 135° from 2'ethyU 
h^methyUhexene.^ 

* Sabatieb and Sbndbbbns, Compt, Rend., 134, 13G9 (1897). 
7 Spkbnt, J. 8oe. Chem, Ind., 3a, 171 (1913). 

* Sabatob and SBNmtBNS, Compt. rend., 134, 1127 (1902). 

* Clark and Jonib, J. Amer. Ckem. 80c., 34, 170 (1912). Clark and 
Ibid., 34» 54 (1912). 



415 CATALYSIS IN ORGANIC CHEMISTRY 154 

Likewise nonene(2) is traDsfonued entirely into nonane}^ 
MethyUpropyUoctene gives the corresponding methyl-propyl" 
octane, and ^-cyclohexyl-heptene, the ^-cyclohexyl-heptane}^ 

415. In the case of phenyl- or polyphenyl-ethylene hydrocarbons, 
when the hydrogenation is carried out with a weakened nickel such 
as is not capable of hydrogenating benzene (56) , or with active nickel 
at 300^, the aliphatic double bonds are saturated without hydrogenat- 
ing the aromatic nuclei. 

Thus styrene, CJEL^ . CH : CHj, gives only ethyl-benzene, 
CJS,^ , CH2CH3. 

The ortho, meta, and para, cre8yl-propene8{2) are regularly 
changed into the ortho, meta, and para cymenes}^ 

l'Phenyl'2-propyl'pentene yields l-phenyl'2'propyl'pentane,^^ 

Stilbene, or symmetrical diphenyl ethylene, C^Ho.CHiCH.CeHB, 
is readily transformed by a slightly active nickel at 240° into dibenzyl, 
CeHg.CHa.CHa.C^Hj. Likewise aa -DiphenyUethylene is readily 
changed to aa-diphenyl-ethane, l^-diphenylr-propeneil) and 1,1- 
diphenyl'propene{2) furnish the corresponding diphenyl-propcmes and 
similar statements hold for the diphenyl-butenes and diphenyl^ 
pentenes}^ 

Ocimene, (CH3),C:CH.CH,.CH:C.CH:CHa, or 2fi'dimethyl'0cta- 

CH3 

triene {2,5,7), of oil of basil is readily hydrogenated over nickel 
at 130-140° to the corresponding 2,6-dimethyl-octane boiling at 
158°." 

416. Unsaturated Alcohols. The fixation of hydrogen fre- 
quently takes place without alteration of the alcohol group. 

Propenol, or aUyl alcohol, CH, : CH . CHgOH, is readily hydro- 
genated at 130-170° over nickel, to give nearly pure propyl alcohol 
containing only a slight amount of propionic aldehyde.^*^ 

Oeraniol, (CH3),C:CH.CH,.CH2.C:CH.CH20H, or 2fi'dimethyl' 

CH3 

octadiene{2fi)oliS), is readily hydrogenated at 130-140° to give the 
corresponding dimethyl-octanoL At the same time a little of it is 
reduced to the saturated hydrocarbon. 

^0 Clabk and Jones, /. Amer, Chem, Soc, 37, 2536 (1915). 

11 MuBAT and Amouboux, J. Pharm, Chim, (7), 5, 473 (1912), C. A., 7, 1494. 

^2 Sabatibb and Mxtbat, Compt, rend., 156, 184 (1913). 

IS Sabatdbb and Mubat, Ann. Chim, (9), 4, 284^297 (1915). 

i« Enklaab, Berichte, 4X» 2085 (1906). 

^s Sabatdb^ Compt. rend., 144, 879 (1907). 



165 HYDROGENATIONS IN THE GAS PHASE 419 

The hydrogenation of linalool, or 2,6-dimethyl-octadiene{2,7)- 
oim, (CH,),C : CH . CH, . CH, . C(OH) . CH : CH„ furnishes the 

CH3 

same products.^^ 

Citronellol, (CH3) ,0 : CH . CH, . CH, . CH . CH, . CH,OH, like- 

CH, 

wise gives dihydrocitronellol}'' 

We have seen (208) that the hydrogenation, over nickel at 200**, 
of secondary a -unsaturated alcohols gives the isomeric saturated ke- 
tone instead of the saturated secondary alcohol, by a simple migra- 
tion of the hydrogen of the alcohol group. 

417. Esters. The esters of unsaturated acids are readily hydro- 
genated over nickel whatever be the position of the double bond. 

Esters of a/^lic acid give esters of propionic at 180°. 

Ethyl dimethyUacrylate likewise gives ethyl isovalerate, and 
ethyl undecylenate, the undecylate. 

It is the same way with ethyl cBnanthylidene-acetate, CeH,, .- 
Cm r CH . CO, • CjHg. 

The same fixation of hydrogen takes place with the esters of im- 
saturated aromatic acids without the hydrogenation of the nucleus. 
Methyl cirmamate, CeH^ . CH : CH . CO, . CH,, gives methyl phenyU 
propionate. 

Ethyl phenyl'isocrotonate, C^B.^ . CH : CH . CH, . CO, . C,H5, 
acts in a similar manner.^® 

418. Ethers of Unsaturated Alcohols. The vapors of allyl 
ether, carried by an excess of hydrogen over nickel at 138-140° are 
totally changed to propyl ether}^ 

Isosafrol, CHa . CH : CH . CeHs^^^^CH,, is hydrogenated in 

the side chain to dihydrosajrol without affecting the ether group.'^ 

419. Unsaturated Aldehydes. Acroleme, CH, : CH . CHO, is 
hydrogenated over nickel at 160° to propionic oMehyde,^^ which can 
be further hydrogenated, by a slower reaction, to propyl alcohol. 

Likewise crotonic aldehyde over nickel at 125° is changed to buty- 

^^ Enelaab, Rec. Trav. Chim, Pays-Bm, 37, 411 (1908), and Berichte, 41, 
2085 (1908). 

17 Hallbr and Martins, Compt. rend,, 240, 1303 (1905). 

18 Dabzbns, CompL rend., 144, 328 (1907). 
10 Sabatieb, Compt. rend., 244, 879 (1907). 

so Hbnbabd, Ch. Wkbld., 4, 630-2; Chem. Cent., 2907 (2), 1512. 
s^ Sabatibb and Sbndbbbns, Ann. Chim. Phys. (8), 4, 399 (1906). 



420 CATALYSIS IN ORGANIC CHEMISTRY 156 

ric aldehyde with a yield of 50%, with about 20% of butyl alcohol 
resulting from the subsequent hydrogenation of the aldehyde.*' 

420. Unsaturated Ketones. The fixation of hydrogen on ethy- 
lene double bonds is so rapid that it can be effected before the ketone 
group, -CO-, is changed to the secondary alcohol group, -CH(OH)-. 

Mesityl oxide, (CH,)sC : CH .CO .CH„ is transformed at 160- 
170^ into 2'^inethyl''pent<mone (4) ,** accompanied by some of the cor« 
responding alcohol and evea of isapentane,*^ Likewise methyl^ 
hexenone, (CH,) ^C : CH . CH, . CO . CH, , gives the corresponding 
methyl-hexanane. 

3"MethyIrhept0ne{3)(me{5) is transformed at 180° into Z-methyU 
heptanone(b) , and likewise 2,4,ft-tnme£AyI^nonene (4) one (6) gives 
the corresponding saturated ketone.** 

Phorone, (CH,),C : CH . CO . CH : C(CH,)„ when hydrogenated 
over nickel at 160-170°, is totally changed to di-iaohutyl-ketane, or 
iaovalerane.** By operating at 225° the ketone is accompanied by 
the alcohol and the saturated hydrocarbon.'^ 

421. By hydrogenating pulegone rapidly over nickel at 140-160°, 
the unsaturated side chain can be hydrogenated without affecting the 
ketone group to give jmlegomenthone: ** 

yCO.CHf \ yCO.CHi \ 

(CH,),C:CC )CH.CH,-^(CH,),CH.CH; J^CH.CH,. 

NCHlCH,/ ^^CHlCH,/ 




Campharane, CHt.CHT )C:C(CHt)t is hydrogenated 

over nickel at 130° to give dihydrocamphorone, boiling at 182° .*' 

422. Unsaturated Acids. Their hydrogenation is readily carried 
out over nickel without any damage to the catalytic metal. The 
vapors of crotonic acid, CH, . CH : CH . COOH, at 190° give butyric 
acid quantitatively. The vapors of oleic acid, carried along by a 
violent current of hydrogen over nickel at 280-300°, are readily trans- 
formed into solid stearic acid, and the same is true of its isomer eldidic 
acid}^ 

ss DouBis, B%M. 8oc. Chim. (4), 9, 922 (1911). 

s< Dabzbns, Compt, rend., 240, 152 (1906). 

s« Sktta, BerichU, 41, 2938 (1908). 

>* BoDBOtnc and Taboubt^ Compt. rend^ 249, 422 (1909). 

>« Sabatob and Mjolbm, Ann. Chim. Phy$. (8), z6, 79 (1909). 

>7 Sktta, Loe, cit. 

>• Halubr and Mabuns, Compt, rend,, 240, 1298 (1905). 

s" GcDCHOT and Taboubt, Compt. rend., 256, 470 (1913). 

*^ Sabactb and Mau^hb, Ann. Chim. Phys. (8), z6, 73 (1909). 



157 HYDROGENATIONS IN THE GAS PHASE 427 

3. The Acetylene Triple Bond 

423. If hydrogen mixed with a small proportion of acetylene is 
passed over cold reduced nickel, the metal becomes warm, the more 
so when the proportion of acetylene is increased. With 2 volmnes 
of hydrogen to 1 of acetylene the spontaneous evolution of heat may 
heat the end of the nickel train to 150^. The contraction of the gas 
is enormous, greater than corresponds to the formation of ethane: 

C2H2 -|- 2I12 "■ CgH^. 

The volume is reduced to one fourth, although a little unchanged 
acetylene and some ethylene remain, showing incomplete hydrogena^ 
tion, because there is produced at the same time a considerable pro- 
portion of higher hydrocarbons, part of which are liquefied. The 
nickel is coated witii a little carbon which is readily separated by 
dilute acids. 

On the contrary, the formation of ethane is complete in the pres- 
ence of an excess of hydrogen. 

424. Inversely if the proportion of acetylene in the mixture is 
increased, the metal heats up more, the liqtdds formed become more 
abimdant and the presence of hydroaromatic and aromatic hydro- 
carbons can be shown. Finally, an incandescence is noticed similar 
to that produced by acetylene alone on nickel (914) *^ 

425. a-H^ptine, or (Bnanthylidene, is readily hydrogenated over 
nickel to n.heptane.^ 

4* The Triple Bond Between Carbon and Nitrogen 

426. The direct hydrogenation of nitriles, R . C : N, easily carried 
out with nickel, leads to the formation of the primary amines, 
R . CH, . NH2, which on account of secondary reactions caused by the 
metal, are accompanied by secondary and tertiary amines. These 
reactions correspond to the formation of ammonia which is eliminated, 
and consequently the secondary amine constitutes the major portion 
of the product. We have: 

2 R.CH2.NH, — NH,+ (R.CH2)2NH 

primary amina seoondazy amina 

and R . CH, . NH, + (R . CH.) ,NH — NH, + (R . CH,) ,N. 

tartiary ^"»t"^^ 

427. Aliphatic Nitriles. Formic^nUrUe or hydrocyanic add is not 

*^ Sabatub and Sendbuns, Compt, rend., ia8» 1173 (1809). 
*' Sabatob and fitemnoNS^ Compt. rend., 135, 87 (19Q2). 



428 CATALYSIS IN ORGANIC CHEMISTRY 158 

affected by hydrogenation except above 250° but then gives the three 
methyl-amines and ammonia. 

AcetomtrUe is readily hydrogenated at 200° and gives a mixture 
containing 60% diethyl-amine, and 20% each of the mono- and tri" 
amines. 

With ethyl cyanide, the dipropyl-amine forms nearly 80% of the 
product. 

Isoamyl cyanide likewise gives chiefly secondary amine, the pri- 
mary being formed in least amount. The amines are accompanied 
by a little isopentane. 

It is evident that the hydrogenation of aliphatic nitriles gives us 
a valuable and convenient method of preparing secondary amines.** 

428. Aromatic Nitriles. The results are not nearly as good with 
aromatic nitriles from which the hydrocarbons and ammonia are 
formed. 

However, the hydrogenation of benzonitrile at 250° gives a certain 
proportion of benzyl-amine and dibenzyl-amine and the same is true 
of p,toliu)-mtrUe which gives a mixture of the primary and secondary 
amines.** 

429. Dicyanides. Ethylene dicyandde, when hydrogenated over 
nickel, gives a certain proportion of tetramethylene-diamine result- 
ing from the regular hydrogenation: 

CN.CH2.CH,.CN + 4H, — NH,.CH,.CH,.CH,.CH,.NH,. 

This is accompanied by a little anmionia and pyrrolidine, 

CH,.CH,\ 

^NH, resulting from its decomposition.** 
CHtCHj/ 

5. Quadruple Bond Between Carbon and Nitrogen 

430. Carbylamines. The aliphatic isocyanides, or carbylamines, 
R . N : C, which former wet reduction methods were unable to hydro- 
genate because they were decomposed by hydration, can add 4H over 
nickel at 160-180° to form the secondary amines, R . NH . CHg 

They are accompanied by a small amount of the primary amine, 
R.CH2.NH2, and the secondary amine, (R.CH2)2NH, resulting 
from the hydrogenation of the nitrile, R . C : N, produced by partial 
isomerization of the isocyanide. 

Methyl carbylamine gives a yield of 80% of dimethyl-amine. 

»» Sabatieb and Sbndkrbns, Compt. rend., 140, 482 (1905). 
«* Fbi^ult, Compt. rend., 240, 1036 (1905). 
«« Gaudion, BuU. Soc. Chim. (4), 7, 824 (1910). 



159 HYDROGENATIONS IN THE GAS PHASE 432 

The metal is gradually coated with tarry material which diminishes 
its activity. 

Ethyl carbylamine gives chiefly methyl-ethyl-andne with a little 
mono- and di-propyl amines. 

Tertiary-butyUisocyanide, (CH3)3C . N j C, hydrogenated at 170- 
180**, gives methyl'tert.butyUamme, which has never been obtained 
by other methods. 

If the reaction is carried on at 220-260**, the secondary amine 
molecule is broken up with the formation of ammonia and hydro- 
carbon.** 

431. Aliphatic Carbimides. It is convenient to consider along 
with the carbylamines the aliphatic carbimidea, or isocyanates, 
R.N: CO (although the hydrogenation is not simply the addition 
of hydrogen but also its substitution for the oxygen atom), because 
the result is the same for both classes. 

Over nickel at 180-190**, the chief reaction is: 

R . N : CO + 3H2 «H,0 + R.NH .CH.. 

But a disturbance is caused by the water produced which reacts 
immediately with a part of the carbimide to form a disubstituted urea, 
(R.NH)jCO, and carbon dioxide. The alkyl urea is immediately 
hydrogenated, giving: 

(R.NH),CO + 3H2 — H2O + NH2.R + R.NH.CH3. 

Hence there is a certain amount of the primary amine, R . NH,, 
and on account of secondary actions of the metal, the secondary, 
RjNH, and tertiary, R3N, also. 

Thus ethyl isocyanate gives a considerable amount of methyl^ 
ethyl-amine, a little diethyUamine, and traces of ethyUamine and 
triethyl'^mine.*'' 

6. Double Bond between Carbon and Oxygen 

432. The carbonyl group, CO, which frequently occurs in organic 
compounds, is readily hydrogenated over nickel to the alcohol ^roup, 
CHOH. 

Aliphatic Aldehydes. Hydrogenated over nickel below 180^, 
these are regularly transformed into the primary alcohols without the 
production of di-secondary glycols or acetals as by-products. 

Formaldehyde vapors at 90® are readily transformed and methyl 

s^ Sabatqib and Mah^hb, Compt rend., 144, 055 (1907). 
'^ Sabatdbb and Mau^hb, Compt, rend., 244, 824 (1907). 



433 CATALYSIS IN ORGANIC CHEMISTRY 160 

alcohol is condensed along with water which is due to the fonnation 
of methane according to the reaction: 

H.C0.H + 2H, — CH. + HA 

But the covering over of the metal surface with a thin coating of 
trioxy-methylene soon suppresses its activity. If the temperature is 
raised, this trouble disappears, but the formation of methane increases 
as well as the decomposition of the formaldehyde itself (508) . 

AcetcUdehyde is readily transformed into alcohol aroimd 140^, but 
at 200^ the destruction of the aldehyde is already apparent. 

Propionaldehyde is regularly hydrogenated to propyl alcohol be- 
tween 100 and 145"^. 

It is the same with isobutyric and isovaleric aldehydes at 135-160^ 
which yield about 70% of the alcohols, the rest of the product being 
imchanged aldehyde with a little acetal. 

433. Aromatic Aldehydes. These do not ^ve this reaction but 
tend to form the hydrocarbons; thus benzaldehyde at 210-235^ ^ves 
benzene and toluene accompanied by a certain proportion of the cor- 
responding cyclohexane compoimds. The reaction which takes 
place is: 

CeH« . CHO + 2H, - CeH. . CH, + H,0 

along with the decomposition of benzaldehyde by nickel: 

CeH, . CO . H — C«He + CO 

followed by a partial hydrogenation of the carbon monoxide to 
methane.** 

434. Pyromucic Aldehyde. Furfural, or pyromucic aldehyde, 
C4H3O . CHO, hydrogenated over nickel at 190**, gives furfuryl alco- 
hol, C^B.fi . CH2OH, accompanied by some secondary products (see 
371 and 487) .»• 

435. Aliphatic Ketones. Aliphatic ketones, being more stable 
towards nickel than the aldehydes, are hydrogenated regularly into 
the secondary alcohols and, unlike their conduct in the classic reduc- 
tion by sodiimi amalgam, they do not form any secondary products 
such as pinacones. The method is an excellent one for the prepara- 
tion of many secondary alcohols, which are produced almost 
quantitatively. 

This process is readily applied to acetone which forms isopropyl 
alcohol at 115-125^ which is thus prepared quite cheaply. It is no 
less good for butanone, diethyl-ketone, methyUisopropyl-ketone, 

** Sabatieb and Sa N ii m NB, Compt. rend., 237, 301 (1903). 

•• Padqa and Ponti, lAncH, 15 (2), 610 (1906), C, 1907 (1), 570. 



161 HYDROGENATIONS IN THE GAS PHASE 438 

methyl'propyl'ketone, and methyUbutyl-ketone. It is only above 
200^ that decompositions of the molecules begin to take place.^^ 

Diisopropyl *'^ and diisobutyl^* ketones are readily transfonned 
into the secondary alcohols under the same conditions. 

When the hydrogenation of ketones is carried out above 200^ 
different results are obtained. Acetone hydrogenated between 200 
and 300^ gives neither isopropyl alcohol nor its pinacone, but chiefly 
methyl-isobutyl-ketone (boiling at 114^) accompanied by diisobutyl- 
ketone (b.l65^).*» 

Methyl'-nonyl'ketone, hydrogenated at 300^, does not ^ve the cor- 
responding alcohol but various products, one of them a ketone, 

436. Alicyclic Ketones, The method is readily applied to these. 
Cyclopentanone is hydrogenated over nickel at 125^ to give 50% 

of cyclopentanol, a little cyclopentane, and 40% of a complex ketone 
formed by the joining of two rings, the cyclopentyUcyclopentanone^' 

The a- and p-methylcyclopentanones are hydrogenated at 150° to 
the corresponding alcohols, accompanied by greater quantities of the 
dimethylcyclopentyl-pentanones formed by the union of two rings.^ 

Cyclohexanone and the three methyl-cyclohexanones are regularly 
hydrogenated below 180° to the corresponding alcohols with small 
amounts of the hydrocarbons.^^ 

/CO.CH,\ 
Pidegomenthone, (CHt)iCH.CHr ;CH.CHi, hydro- 

^vCHi.CH,/ 

genated by an active nickel at 140-160°, gives a mixture of menthol 
and pulegomenthol.^^ 

437. Ketcacids. Laewiinic acid, CH, . CO . CH^ . CH, . COOH, 
hydrogenated over nickel around 250°, gives the hydroxy-acid, which 
loses water to form valerolactone, CH. . CH . CHj . CH, . CO.** 

I 1 

438. Diketones. The results of the hydrogenation of tiiese de- 
pend on the nature of the compoimds.'* 

^ Sabahkb and Sbndboinb, Compt, rend,, Z37» 302 (1903). 

♦1 Amouboux, BuU, 8oc. Chim, (4), 7, 164 (1910). 

^ Mah^hs, Bun. 80c. Chim. (4), 15, 327 (1914). 

^ Labsoub, Compt. rend., 156, 795 (1913). 

M Halubr and Labbusur, Compt. rend., 250, 1017 (1910). 

^ GkM>CHOT and Taboubt, Compt. rend., 15a, 881 (1911). 

^ GoDCHOT and Taboubt, BvU. Soc. Chim. (4), 23, 591 (1913). 

^7 Sabahkb and Sbndbbnb, Ann. Chim. Phyn. (8), 4» 402 (1906). 

48 Hallbb and Mabunb, Compt. rend., 240, 1298 (1906). 

«* Sabatob and Mau^hb, Ann. Chim. Phya. (8), 26, 78 (1909). 

^^ Sabatdb and Mau^hb, Compt. rend., 244, 1066 (1907). 



439 CATALYSIS IN ORGANIC CHEMISTRY 162 

a-Aliphatic Diketones, Diacetyl, or butanedione, CH3 . CO .- 
CO . CHg, by hydrogenation at 140-150°, is totally transformed into 
a mixture of butanol-one (2,3) , CH. . CH (OH) . CO . CH,, and 
butanediol(2,3), CH, . CH(OH) . CH(OH) , CH3. 

439. 'Aliphatic Diketones. Acetyl-acetone, CHg . CO . CHj .- 
CO.CHg, when hydrogenated at 150°, gives two simultaneous re- 
actions. One part is normally hydrogenated to form pentoli2)(me{^), 
CHg . CH(OH) . CH2 . CO . CHs, while the larger portion is split into 
two fragments: 

CH,.CO.CH,.CO.CH3 + H,«CH,.CO.H + CHa.CO.CH3. 

The acetaldehyde and acetone thus formed are then reduced to 
ethyl and isopropyl alcohols, 

Methyl-acetyl-acetone, CHg . CO . CH (CH3) . CO . CH3, forms 
hardly anything but the decomposition products. 

440. 7 -Aliphatic Diketones. AcetonyUacetone, CH3 . CO . CHj .- 
CHj.CO.CHj, when hydrogenated at 190°, is totally trans- 
formed, not into the corresponding diol but into the ether^ 
CH, . CH . CH2 . CH2 . CH . CH3, produced by its dehydration. 

I O •' 

441. Aromatic Ketones. Aromatic ketones and diketones give 
the corresponding alcohols by hydrogenation but go chiefly into the 
hydrocarbons (389 et seq.), 

442. Quinones. We can consider qvinones as imsaturated alicy- 
clic diketones. They are readily hydrogenated by nickel at 200°, 
and add H, to form the corresponding diphenols in excellent yields. 

This is the case with ordinary qidnone which gives hydroqvmone 
quantitatively, with toluquinone, with p,xyloquinone, and with thymo- 
quinone. 

But if the operation is carried on at a higher temperature, 220 to 
250°, the diphenol is no longer obtained, but water, the monophenol, 
and even the hydrocarbon.'^ 

443. Ethylene Oxides. The direct hydrogenation of these oxides 
is doubtless readily carried out in all cases. 

In the particular case of the ether of cyclohexanediol{l^) , hydro- 
gen is added at 160° to give a quantitative yield of cyclohexanol: '* 

CH2 . CH2 . CH\ CH2 . CH, . CHOH 

CH2 . CH2 . CH/ CH2 . CH2 . CH2 

'^ Sabatier and Mailhb, Compt. rend,, 146, 457 (1908). 
•2 Bbunbil, Ann, Chim, Phys, (8), 6, 237 (1905). 



163 HYDROGENATIONS IN THE GAS PHASE 446 

7. The Aromatic Nucleus 

444. The direct hydrogenation of the aromatic nucleus has long 
been considered very difficult to accomplish. When benzene is re- 
duced by concentrated hydriodic acid at 260°, cyclohexane, C«Hi2, 
is not produced as was hoped, but its isomer, methyl-pentamethylene, 
boiling at 69®, is formed by a molecular rearrangement."* However, 
this method of reduction has been successfully used with toliLene and 
m,zylene which give certain amounts of the corresponding saturated 
cyclic compounds. But this formation is very difficult and most of 
the aromatic hydrocarbons can not be hydrogenated in this way. 
The hydroaromatic hydrocarbons might be separated from Baku 
petroleum by laborious fractionations or prepared by tedious 
synthetic processes. 

The direct hydrogenation of phenol and of its homologs had never 
been accomplished, nor had that of aniline and related aromatic 
amines. 

On the contrary, benzoic and the phthalic acids had been hydro- 
genated by sodium amalgam. 

445. In 1900, Limge and Akunoff showed that combination takes 
place when a mixture of benzene vapor and hydrogen is passed over 
platinum black in the cold, or better, at 100°, and calculated from the 
decrease in volume of the mixture that cyclohexane, C^Hja, must have 
been formed although the same reaction with platinum sponge gave 
only cyclohexeney C^Hio- But the activity of the catalyst was quickly 
exhausted, and they were not able to isolate any product of the hydro- 
genation.'* 

The use of reduced nickel enables us to hydrogenate the aromatic 
nucleus regularly in most cases. This hydrogenation ordinarily takes 
place around 180° without isomerization and usually without side 
reactions, hence with good yields. This is without doubt the most 
important service rendered by reduced nickel. 

446. Aromatic Hydrocarbons. The direct hydrogenation of 
benzene to cyclohexane, C^Hu, takes place with nickel above 70°. 
Its speed increases with the temperature up to 170-190°, where it is 
rapid without any side reaction. Above that, and particularly above 
300°, a part of the benzene is reduced to methane and carbon is de- 
posited on the nickel. 

Cyclohexane is sometimes obtained at once, but usually it contains 
some benzene which has escaped the reaction and which is more 

ss KiBHNKB, /. prakt. Chem. (2), 56, 364 (1897). 

>« LuNGB and Akun<»t^ Zeit. anorgan. Chem., 34, 191 (1900). 



447 CATALYSIS IN ORGANIC CHEMISTRY 164 

abundant the more worn out the nickel is. Treatment with a mixture 
of 1 volume fuming nitric acid to 2 volumes concentrated sulphuric 
acid easily removes the benzene.*' 

447. All of the homologs of benzene are hydrogenated over nickel 
at 150 to 180^, being transformed into the homologs of cyclohexane. 

Below 250^ the hydrogenation takes place without any complica- 
tions with the methyl derivatives of benzene, toluene, ortho, meta, 
and para xylene, mesitylene and psevdocumene, the yields of the cor- 
responding methyl cyclohexane derivatives being practically quanti- 
tative, though traces of the aromatic hydrocarbons remain. These 
may be readily eliminated by shaking with the nitric-sulphuric acid 
mixture which has little effect on the saturated hydrocarbons in the 
cold. 

448. But if we start with substituted benzenes containing long 
side chains, ethyl, propyl, isopropyl, and butyl, while the correspond- 
ing derivative of cyclohexane is always the chief product, there is 
always more or less of the saturated hydrocarbon resulting from the 
shortening of the long side chain. Thus ethyl-benzene gives, along 
with ethyUcyclohexane, a little methyUcyclohexane with correlative 
formation of methane. Propyl-benzene gives a little ethyl- and 
methyl-cyclohexane. This disturbance is more serious when the long 
side chain is a branched one, e. g,, isopropyl. Thus with p.cymene 
which is p.methyl'isopropyl-bemene, along with about 66% of 
pjmethyUiiopropyUcyclohexane, about 16% each of pMmethyU and 
p.methyl'ethyl'Cyclohexane are obtained. 

This formation of by-products which is due to the power that the 
nickel has of dissociating the molecules, is greater with higher tem- 
perature, and for that reason it is best not to go above 180^. 

449. By this method, methyl-cyclohexane, the three dimethyl- 
cyclohexanes, 1,3,5- and 1^3 jir-trimethyl-cyclohexanes, propyl-cyclo- 
hexane, p.methyl-ethyl-cyclohexane, isopropyl-cyclohexane, the three 
methyl-isopropyl-cyclohexanes or menthanes, and dimethyl-isobviyl'' 
cyclohexane have been prepared."^ 

450. Above 250^, and particularly above 300^, the production of 
the cyclohexane hydrocarbons diminishes and then disappears alto- 
gether since the inverse dehydrogenation begins and becomes more 
and more rapid (641). 

451. Phenyl-ethylene, styrene, or cinnamine, CeHg . CH : CHg, is 

BB Sabatieb and Sbndebbns, Compt, rend*, X3fl, 210 (1901). 

^ Sabatub and Sbniubbbnb, Compt. rend., 133, 566 and 1254 (1901). 
Sabatdb and Mubat, Compt. rend., 156, 184 (1913), and Ann. Chim. (9), 4, 271 
(1915). 



165 HYDROGENATIONS IN THE GAS PHASE 463 

hydrogenated at 160^ by an active nickel to ethyUcyclohexane. With 
a slightly active nickel around 200^ hardly anything but ethyU 
bemene is obtained."^ 

Phenylrocetylene, CJEL^ . C i CH, hydrogenated over nickel at 
180®, gives almost exclusively ethyl-cyclohexane^^ 

452. Polycyclic Aromatic Hydrocarbons. Hydrogenation over 
active nickel at about 170'' permits the addition of 6 atoms of hydro- 
gen to each aromatic nucleus. The low volatility of the polyphenyl 
hydrocarbons, which do not boil except at temperatures above 250®, 
makes it necessary to carry their vapors along by a large excess of 
hydrogen. A single passage over the nickel imder the conditions used 
for benzene does not effect complete hydrogenation and it is usually 
necessary to repeat the process with the product. 

However, a single operation is all that is required to transform 
diphenyl-methane, CeHg . CH, . CeH,, into dicyclohexyUmethane, 
CeHjx . CH2 . C^H^j. *• 

With diphenyl, CaHg.C^Hj, Eijkman** obtained only phenyl- 
cyclohexane, CeH^ . CeH^i, boiling at 240®, but Sabatier and Murat 
have succeeded in transforming it into dicyclohexyl, CeH^^ . CeH^^, 
melting at 4® and boiling at 233® and almost imattacked by the mix- 
ture of nitric and sulphuric acids.^^ 

Likewise symmetrical diphenyUethane, or dibenzyl, C^H^ . CH, .- 
CH^.C^Hs, has been completely transformed into l^r^icyclohexyU 
ethane, CJB,^^ . CH, . CH, . C«Hii, boiling at 270®. The l.l-diphenyU 
ethane, (CeH,) ,CH . CH,, is changed with greater difficulty into the 
lyl'-dicydohexylrethane boiling at 256®. 

The four diphenyl-propanes are more or less readily transformed 
into the dicyclohexyUpropane% over nickel at aroimd 170®. 

Only in the case of dimethyUdiphenyUmethane, (C«H5),C(CH,)2, 
a quaternary hydrocarbon, is there any notable breaking up of the 
molecule into isopropyl^yclohexane, ethyl-cyclohexane, methyl- 
cyclohexane and even cyclohexane. 

Five diphenyl-bvtanes have been easily hydrogenated over active 
nickel at 170®, to the corresponding dicyclohexyl-butanes, and like 
results have been obtained with three diphenyl-pentanes which do not 
boil below about 300®." 

453. According to whether the temperature is higher or lower, 
triphenylrfnethane, CHCCeH,),, gives first dicyclohexyl-phenyl- 

^f Sabatob and Sbnimbbns, Campt. rend,, 233, 1255 (1901). 
** Sabatob and Sbndebbnb, Compt. rend., 235, 88 (1902). 
>« EuKMAN, Chem. Weekblad, 1, 7 (1903), C, 1903 (2), 969. 
M Sabatibi and Mxtsat, Compt rend., X54» 1390 (1912). 
<^i Sabatib and Mubat, Ann. Chim. (9), 4» 903 (1915). 



164 CATALYSIS IN ORGANIC CHEMISTRY 166 

methane, CJ3.^ . CH(CeHii)2, and then tricyclohexyl-methane, 
CH(CeH,,),." 

On the contrary, the hydrogenation of symmetrical tetraphenyl- 
ethane, (CeH5)2CH.CH(CeHB)2, has miscarried, since imder the in- 
fluence of very active nickel at 230-240®, it yields only dicyclohexyU 
methane produced by the hydrogenation of the two halves of the 
molecule.** 

454. Hydrindene, which can be regarded as benzene with a satu- 

/cav. 

rated side chain, CJEL^^ /CH2, adds 6 atoms of hydrogen 

to form dicyclononane, C^H^e) boiling at 163°.** 

CeHgv 
Fluorene, • /CHi, over nickel at 150®, furnishes only the 

decahydro'fiuorene boiling at 258®.*" 

455. Aromatic Ketones. With an active nickel at a moderate 
temperature, the -CO- group is changed to -CHa- and the aromatic 
rings are hydrogenated (389) . 

Thus acetophenone gives ethyUcyclohexane, 
DibemyUketone, CJEL^ . CHj . CO . CHg . CeHj, with active nickel 
at 175®,** can give immediately synmietrical dicyclohexyl-propane, 

CJO-i^ . Cxi2 • Cxi2 . CII2 . Cglljj. 

456. Phenols. The direct hydrogenation of the aromatic nucleus 
can be readily accomplished in phenol and its homologs by the use 
of nickel. 

Phenol, hydrogenated at 180®, gives immediately cyclohexanol, 
CeHji . OH, containing 5 to 10% unchanged phenol, small quantities 
cyclohexanone and cyclohezene, C^Hio- The mixture boiling between 

165 and 165® can be purified by a second passage over the nickel at 
150-170® which changes the phenol and cyclohexanone completely into 
cyclohexanol.*^ 

457. o.Cresol is regularly transformed by nickel at 200-220® into 
o.methyl-cydohexanol with a yield of better than 90%. There is 
a little of the ketone which can be extracted with sodium bisulphite. 

m.Cresol, under the same conditions, gives a mixture of the alcohol 

« GoDCHOT, CompL rend., 147, 1057 (1908). 

«« Sabatibb and Murat, Compt, rend,, 157, 1497 (1913). 

w EuKMAN, Chem. Weekblad, x, 7 (1903), C, 1903 (2), 989. 

«B Schmidt and Metzqer, Berichte, 40, 4566 (1907). 

** Sabatieb and Murat, Compt. rend,, 255, 385 (1912). 

^7 Sabatisb and Sbnoesens, Compt, rend., 1^7 f 1025 (1903). 



167 HYDROGENATIONS IN THE GAS PHASE 461 

and ketone which can be rehydrogenated at 180** to give practically 
pure m.methylrcycloheoMinoL 

p.Cresol is readily hydrogenated at 200-230° to form p.methyl" 
cyclohezanol containing only traces of the ketone which are readily 
eliminated by bisulphite.*® 

458. The xylenols, or dimethyl-phenols, are hydrogenated over 
nickel with varying degrees of success. lf^Diinethyl-phenol(4) ^ at 
190-200°, changes almost completely to the corresponding dimethyl- 
cyclohexanol with a little ketone and m.xylene. 

The same may be said of the ly4r-dimethyl'phenol{2) , which gives 
the corresponding cyclohezanol with about 10% of the ketone. 

1 ^-Dimethyl-phenol (4) , hydrogenated under the same conditions, 
gives only about 26% of the desired cyclohexanol, about 8% of the 
ketone, while about 67% is reduced to ojjcylene?^ 

459. In the same manner with an active nickel at below 160° the 
regular hydrogenation of p, butyl-phenol^ methyUhutyl-phenol, one 
dim^thyl-hutyl-phenol,'^^ and one diethyl phenol ^^ have been hydro- 
genated into the corresponding cyclo-aliphatic alcohols. 

Thymol is satisfactorily hydrogenated to hexahydrothymol at 
180-185°. 

The same may be said of its isomer carvacrol, which is hydrogen- 
ated at 195-200° to hezahydrocarvacroU^ 

460. Polyphenols. The addition of 6H to the nucleus in poly- 
phenols is difficult to realize by the use of nickel, doubtless because 
the desired reaction can be effected only between narrow temperature 
limits. At 200° the hydrogenation leads to phenol and benzene, 
mixed with cyclohexanol and cyclohexane, without any appreciable 
amount of the desired cycloaliphatic diols or triols.'^® 

461. On the contrary, by lowering the temperature to aroimd 
130°, the normal addition of hydrogen can be accomplished in some 
cases. 

Hydroquinone at 130°, givea exclusively cyclohexadiol (1,4), or 
quinite, as the cis form, but if the hydrogenation is carried on at 160°, 
a mixture of the ci& and trans forms is obtained with some phenol 
and cyclohexanol, 

Pyrocatechin, at 130°, gives exclusively cyclohexadiol{lfi), melt- 
ing at 75°. 

^s Sabatieb and Mau^hb, Compt, rend*, 240, 360 (1005). 

^^ Sabatieb and MAniHH, Compt, rend,, 142, 55Z (1906). 

70 Darzbns and Host, Compt, rend,, 153, 607 (1911). 

7^ Hbndebson and Botd, /. Chem, 80c,, 99, 2159 (1911). 

7> Bbunsl, Compt, rend,, 137, 1268 (1903). 

7* Sabahbb and Sbndsbbnb, Ann, Chim. Phya, (8), 4, 428 (1905). 



462 CATALYSIS IN ORGANIC CHEMISTRY 168 

Reaordne is difficult to hydrogenate at low temperatures on 
account of its slight volatilityi but small amounts of cydohexa- 
dial (1,3), melting at 65°, have been isolated.^* 

462. Pyrogallol, at 120-130'', gives cyclohexatriol{i;2,Z) , melting 
at 67° J* 

463. Thymoquinol, CaHT(CH,)CeH,(OH)j, is hydrogenated by 
nickel to menthane^iol(2J5) , melting at 112°.^' 

464. Ethers of Phenol. By means of nickel, below 150°, we 
may accomplish the direct hydrogenation of phenol ethers without 
breaking up the molecules. 

Thus avMol, CeHg . OCH„ gives methoxy^cyclohexane, CeH^i .- 
OCH3. The methyl ethers of the cresols are transformed into the 
corresponding methoxy-methyl'Cyclohexanols. Phenetol gives ethoxy- 
cydohexanoV* 

465. Aromatic Alcohols. Up to th« present, the hydrogenation 
over nickel has not been accomplished without eliminating the hy- 
droxyl group. Thus benzyl alcohol gives toluene and methyl-cydo" 
hexane. 

p.Tolyl-diniethyl-carbmol, CH, .CeH^.CCOH) (CH,),, changes 
to hexahydrocyrnene, identical with menthane, when hydrogenated at 
150°." 

466. Aromatic Amines. On hydrogenating aniline at 190°, 
ammonia is evolved and a nearly colorless liquid with strong ammo- 
niacal odor is obtained which gives on fractionation: 

1. A little benzene and cyclohexane, going over around 80°, 

2. About 30% of cyclohexyl-^mine, CeHii . NH,, boiling at 134°, 

3. A small amount of unchanged aniline, boiling at 182°, 

4. A portion boiling above 190°, consisting of about 30% 
dicyclohexyl-amine, boiling at 252°, and about 30% of cyclo- 
hexyl-atdline, boiling at 279°, and a little diphenyl-^Lmine, boiling 
at 311°. 

The dicyclohexyl-amine comes from the decomposition of the 
cyclohexyl-amine by the nickel, with elimination of ammonia, simi- 
lar to what has been mentioned in connection with the hydrogenation 
of nitriles (426). The cyclohexyl-aniline and the diphenyl-amine 
can be regarded as produced by the partial dehydrogenation of the 
dicyclohexyl-amine.^' 

Y* Sabatub and Mjjlhm, Compt. rend., 146, 1103 (1008). 
76 Hbndbbbon and Sxtthbuand, /. Chem, 80c., 97, 1616 (1010). 
T* Bbxtkbl, Ann, Chim, Phya. (8), 6, 205 (1005). Sabatibr and SiNDmaNB, 
BuU. Sac. CMm. (3), 33» 616 (1005). 

7^ Smirnoy, /. Russian Phys, Ckem. 80c., 41, 1374 (1000). 
^> Sabatieb and Sbndbbns^ Compt, rend., X38» 457 (1006). 



169 HYDROGENATIONS IN THE GAS PHASE 470 

467. The toluidines, CH, . CeH^ . NH,, are more difScult to hydro- 
genate than aniline, but appear to give similar results. 

By operating with mXohdime (boiling at 197^) over nickel at 
200^, we obtain, along with a little methyl-cyclohexcme, boiling at 
101^, and unchanged m.toluidine, a considerable amount of metho" 
cyclohexyl-amine, CH, . CeH^o • NH,, boiling around 150^ and having 
an intensely alkaline reaction, and higher alkaline products boiling 
at 145 and 175^ respectively under 20 mm. pressure, which are doubt- 
less dimethocyclohexyUamine and methocyclohexyUaniline. But the 
activity of the nickel falls off rapidly to nothing. This effect is even 
more marked with artho and para toluidines and with the xyUdines, 
whether these amines contain toxic substances or whether slightly 
volatile products of the reaction remain on the surface of the nickel 
and suppress its activity.^* 

468. The hydrog^nation of the nucleus by nickel at 160-180^ is 
more readily accomplished for anilines substituted in the NHj- group. 
The most difficult of these is methyUaniline which gives a rather 
moderate yield of cydohexyl-methyUamine. A secondary reaction, 
which becomes more and more important as the temperature is raised, 
tends to produce the aliphatic amine, with the simultaneous libera- 
tion of cyclohexane or benzene. 

Much more satisfactory results are obtained with ethyl^anUine, 
which gives cyclohexyl-ethyl'amine, boiling at 164^, with dimethyl- 
aniline, which leads to cycloheocyl-dimethyl'^Lmine, boiling at 165°, 
and with diethyl-amline which yields cydohexyl-diethyl^ndne, 
boiling at 193**.*« 

469. Diphenyl^imine, (CeH5)2NH, when submitted to hydrogena- 
tion over nickel at 250°, is decomposed into ammonia and cyclohexane. 
But by working at 190-210° with vapors of diphenyl-amine carried 
along by a large excess of hydrogen, it is possible to accomplish a 
regular hydrogenation, producing cydohexyUanUvne and dicydohexyl- 
amine, accompanied by certain amounts of cyclohexane, cyclohexyl- 
amine, and even aniline, resulting from the breaking up of the mole- 
cule by nickel.** 

470. Benzyl-amine, such as is usually obtained by various methods 
of preparation, can not be hydrogenated over nickel without break- 
ing up of the molecule into ammonia and toluene, even below 100°. 
The cause must be the presence of foreign substances which injure 
the catalyst, since the normal hydrogenation can be realized with 

7* Sabatibi and Sbndbbbnb, Ann. Chim. Phys. (8), 4, 387 (1905). 
*o Sabatdeb and ^ndbbbnb, Compt. rend., Z38» 1257 (1904). 
*^ Sabatub and Sbnubbbkb, Ann. Chim. Phys. (8), 4, 483 (1905). 



471 CATALYSIS IN ORGANIC CHEMISTRY 170 

benzyl-amine obtained by the catalytic action of thoria on a mixture 
of ammonia and benzyl alcohol vapors, and hexahydrobenzyl-^Lmvne 
is obtained, accompanied by dihexahydrobenzyl^amine^* 

471. Aromatic Acids. Direct hydrogenation over nickel fails 
when it is applied to benzoic acid or its homologs. When the vapors 
of benzoic add, carried along by an excess of hydrogen, are passed 
over a very active nickel at 180-200**, the production of a little 
cyclohexane and traces of hexahydrobenzoic acid is observed at the 
start, but after a very short time the benzoic acid passes on un- 
changed, the surface of the nickel having doubtless become coated 
with a stable benzoate.*' 

Sabatier and Senderens failed likewise in the hydrogenation of 
the eaters of benzoic ddd, as the nickel rapidly became inactive. But 
by operating with the metal block at a perfectly regulated tempera- 
ture below 170^, Sabatier and Murat have succeeded in accomplishing 
the regular hydrogenation of methyl benzoate, and even more readily, 
the hydrogenation of the esters of higher alcohols, and have thus ob- 
tained methyl, ethyl, isobutyl, and iaoamyl hexahydrobenzoates, the 
iaoamyl ester in 80% yield. The saponification of these esters yields 
the hexahydrobenzoic add immediately.** 

By the same method, they realize the complete hydrogenation 
of esters of phenyUacetic acid to those of cyclohexyUacetic at 170- 
185^,"' of esters of hydrodnnamic acid to esters of fi^cyclohexyU 
propionic,^^ and finally of esters of ortho, meta, and para tohdc acids 
to those of the corresponding hezahydrotoluic acids. 

8. Various Ring Compounds 

472. Trimethylene Ring. Cyclopropane, or trimethylene, 

yjHi, is hydrogenated by nickel above 80®, and rapidly at 
OH*/ 
120°, to form propane.^^ 

Likewise ethyUtrimethylene is hydrogenated by nickel to 

ieopentane: 

• X^H.CHj.CHs — ► yCH.CHj.CHj. 

CH»/ CH,/ 

83 Sabatisb and Mkruan^ Compt. rend., 153, 160 (1911). 

^ Sabatibb and Mxtbat, Compt. rend,, 154, 923 (1912). 

^ Sabahbb and Mubat^ Compt. rend., 154, 924 (1912). 

80 Sabatodb and Mubat, Compt. rend., 156, 424 (1913). 

8* Sabatibb and Mubat, Compt. rend., 156, 751 (1913). 

87 WniJSTATm and Kamktaxa, BerichU, 41, 1480 (1908). 

^ Eokakov, /. Rrutian Phya. Chem. 8oc., 48, 168 (1916), C. A^ zz, 454. 



171 HYDROQENATIONS IN THE GAS PHASE 476 

Methyl^cyclopropene yields isobutane at 170-180° : ** 

CH ^ ^^\^ 

Dimethylmethylene-cyclo'^opafifi gives Uohexane at 160° : ^ 

CH,v 

• )C:C(CH.), -> CH,.CH,CH,CH(CH.)i 
CH»/ 

473. Tetramethylene Ring. CycZobtitone furnishes butane, 
while cyclobutene, at 180°, passes first into cyclobutane and then into 

474. Pentamethylene Ring. CychpeyUadiene is regularly hy- 
drogenated to cycloperUane.^* 

476. Hexamethylene Ring. Cydohexene, CeHio, is readily re- 
duced to the cyclohexane condition by nickel below 180°. The same 
is true of the cyclohexadienes. 

All the cydohexene hydrocarbons are readily hydrogenated by 
nickel to the cydohexane hydrocarbons. Thus the ethylene hydro- 
carbons formed from the three dimethyl-cydohexanols readily 
furnish the three dimethyl-cyclohexanes.*' MethyUethyl-lfi'CydO' 
hexene regularly passes into the corresponding saturated deriva- 
tive.** 

Menthene, CH, . CeHs . CaHy, submits to regular hydrogenation 
at 175° to ^ve p.methyl-isopropyl^cydohexQne, or menthane, iden- 
tical with that formed from cymene and accompanied by certain 
amounts of the same secondary products *' (448) . 

Phenyl'Cydohexeheilyl) is readily changed to phenyl-cydohexane 
by a slightly active nickel. The same is true of cydohexyUcydo^ 
hexene (lfl)y which furnishes dicydohexyl.^ 

476, Aoetyl^cydohexane, CH« . CO . C^Hn , is hydrogenated by 
nickel at 160°, without affecting the ketone group, to give hexahydro- 
acetophenane.^^ 

Ethyl tetrdhydrobenzoate, CqHq . CO^CsHs, is transformed into 

B9 MusHKOwsKi, /. Runian Phys, Chem. 8oc., 46, 97 (1914), C. A., S, 1965. 

M Zdjnbxt, BerichU, 40, 4743 (1907). 

*^ WnxsTATTB and Bbucb, Berichte, 40, 4406 (1907). 

9» EuKMAS, Chem. Weekblad, i, 7 (1903). 

•s Sabatdeb and 'Mjolbm, Ann. CMm. Phya. (8), zo, 552, 555 and 559 (1907). 

•* MuBAT, BvU. 80c. Chim. (4), x, 774 (1907). 

*> Sabatibb and Sbndibbnb, Compt. rend., 232, 1256 (1901). 

*• Sabatobb and Mxtbat, Compt. rend., 154, 1390 (1912). 

*^ Dabzbnb and Rost, Compt. rend., xsz, 758 (1910). 



477 CATALYSIS IN ORGANIC CHEMISTRY 172 

ethyl hexahydrobemoate, and the ester of cyclohexene^acetic acid, 
CeHo . CH, . COsH, into that of hexahydrophenyl<tcetic acid.** 

Carvone adds hydrogen to its double bond and its ketone group 
passes into the alcohol, forming a mixture of hydrocaruols.^ 

477. Terpenes. The terpenes with two double bonds add 211, 
with nickel at 180^, while the terpenes with one double bond usually 
add only H,. 

Limonene gives menthane, identical with that from menthene and 
cymene with the same secondary products. The same is true of 
sylvestrene and terpinene, 

Pinene is readily transformed at 170-180^ into dihydropinene, 
^lo^iBi boiling at 166^, identical with that prepared by the action of 
hydroiodic acid (Berthelot). 

The camphene (from an unknown source), melting at 41^, studied 
by Sabatier and Senderens, added H^ with difficulty at 165-176^ to 
furnish a camphane, CioH^s) boiling at 164° and appearing to be 
identical with that which Berthelot had previously isolated.^** 

The camphene from pinene hydrochloride gave a mixture of a 
solid camphane, melting at 65-67°, and liquid camphane, boiling at 
160°."* 

An inactive camphene melting at 47-49° was transformed into a 
solid camphane, melting at 60°, by a single hydrogenation over 
nickel."* 

478. Terpineol, hydrogenated over nickel, even at a low tempera- 
ture, around 125°, is changed to hexahydrocymene}^* 

^H.CHiv 
a-Thujene, CHj.Cf^ / -^.CH(CH8)i, changes into Aexa. 

hydrocymene}^ 

479. Heptamethylene Ring. Cycloheptadiene, CjE^^y hydro- 
genated over nickel at 180°; yields only cycloheptane, stable even 
with prolonged hydrogenation at 200°, but at 235° it seems to 
isomerize into methyl-^yclohexane}^' 

480. Octamethylene Ring. Cyclo-octadiene, CgH^s, hydroge- 
ns Dabzinb, Compt. rend^ 244, 828 (1907). 

** Halueb and Mabtiks, Compt. rend., 240, 1902 (1906). 
^^ Sabatieb and Sbnmbrinb, Compt. rend., 232, 1266 (1901). 
^01 Lffp, Annalen, 38a, 265 (1911). 

^^* NAMXfTKiN and Miss Abaumovskata^ /. Ruman Phys. Chem. 80c., 47» 
414 (1915), C. A., 20, 45. 

^os Haludb and Mabtins, Compt. rend., 240, 1393 (1905). 
104 ZnjNBXT, /. Ru8nan Phya. Chem. 80c., 36, 768 (1904). 
106 WujSTlTsm and Eambkata^ Berichte, 42, 1480 (1908). 



173 HYDROGENATIONS IN THE GAS PHASE 484 



le) 



109 



nated very slowly over nickel at 180^, gives cyclo-^octcme, CgH 
which further hydrog^nation at 200-250^ appears simply to isomerise 
into dimethyl'Cyclohexane}^'' 

Bicyclo-octene, at 150^, furnishes bicyclo-octane, boiling at 

481. Naphthalene Nucleus. Naphthalene is transformed at 200^ 
by nickel into tetrahydronaphthalene,^^^ boiling at 205°,*" while at 
175°, decahydronaphthalene, or naphthane, boiling at 187°, is 
formed-*** 

a-Naphthol, by means of two successive hydrog^nations at 170° 
and 135°, respectively, is transformed into decahydro-a-naphthol, 
melting at 62°. 

Likewise by hydrogenation at 170° and then at 150°, ]3-naphthol 
yields decahydro-jS-naphthol, melting at 75°.*** 

482. Acenaphthene, Ci^Hef | s, which is related to naphthalene 

in constitution, is transformed by nickel at 210°, as well as at 
250°, into the tetrahydro^, C^fi^^, boiling at 254°.**' 

483. Anthracene Nucleus. Anthracene is hydrogenated in steps, 
more hydrogen being taken up at lower temperatures. At 280° 
teirahydroanthracene, Ci^Hj^, melting at 89°, is formed, while at 200°, 
octohydroanthracene, melting at 71°, is obtained. By using a very 
active recently prepared nickel, it is possible to transform the octo- 
hydro-- into perhydroanthracene, Ci4H,4, melting at 88°.*** 

484. Phenanthrene Nucleus. Phenanthrene, Cj^Hio, hydrogen- 
ated at 160° over a very active nickel, gave a mixture of the hexa- 

io« WttLSTATim and Vibaguth, BerichU, 40, 067 (1907). 

^07 WnxsTATTBB and Wabb, BerichU, 44> 3^44 (1911). 

108 WniiKTATEBB and Vibaguth, Berichte, 4X» 1480 (1008). 

i<^» The tetrahydro has d. QJdW^ and boils at 205-207* and is known as 
tetralin while the dekahydro is known as dekalin and has d. 0.8827>^ and boils 
at 180-101*. Tetralin spirits is a mixture of the two. These are coming to be 
important as turpentine substitutes, particularly in Europe. See mt Kbqhbl, 
Rev. chim. ind., ag, 17^-178 (1020), C. A., 14, 3803; also Shroetibb, Annalen, 4^6, 
1 (1022).— E. E. R. 

^^^ Sabatieb and Sbndibbns, Compt. rend., zsa, 1257 (1001). 

^1^ Lbboux, Compt. rend., 139, 672 (1004). 

1" I^boux, Compt. rend., 141, 053 (1005). Ann. Chim. Phys. (8), ax, 483 
(1010). 

^is Sabatzbb and SbNixBBBKS, Compt. rend., 132^ 1267 (1001). CkmcHor, 
BvU. 80c. Chim. (4), 3. 520 (1006). 

^ QoDCHor, Arm. Chim. Phya. (8), za, 468 (1007). 



486 CATALYSIS IN ORGANIC CHEMISTRY 174 

hydro-, boiling at 306^, and the octohydro-, Ci^Hi,, boiling at 280^."* 
These results are different from those obtained by Schmidt and 
Metzger; who got only dihydrophenanthrene at 150^/^* and from 
those of Padoa and Fabris, who obtained a mixture of the solid 
dihydro- and the liquid tetrahydro- at 200^, but were able to get the 
dodecahydrch- at 175°."^ 

485. Complex Rings. Pyrrol, when hydrogenated over nickel at 
180-190^, gives 25% of pyrrolidine, C^HqN^ with a small quantity of 
a substance which appears to be hexahydro-indoline}^^ 

486. Pyridine is only slowly attacked by hydrogenation over 
nickel between 120 and 220^ , and does not yield any yvperidiM; 
there is opening of the ring with the formation of some amyUamine.^^ 

487. Fyrfuryl-ethyUcarbinol yields tetrahydroftarftaryl-ethyU 
carbinol on hydrogenation at 175°.*** 

MethyUa-iujurane adds 2H, at 190^ to ^ve tetrahydro-methyl" 

CHi.CHa\Q 
a-jurjurane, \ / . If the hydrogenation is pushed, 

CHs . CM CHs 

the ring is opened and methyt-propyUketone is formed^ finally methyU 
propyUcasrbinol, or pcntonoi(2)."^ 

488. QuinoUne, when hydrogenated over a very active nickel at 
160-190°, adds 2H2 to the pyridine ring to form tetrahydroqmnoline 
in excellent yield. 

Likewise ^-methyl^qvinoline is readily hydrogenated to the corre- 
sponding methyl'tetrahydroqtdnoline}*^ 

By carrying out the hydrogenation at 130-140®, over a very ac- 
tive nickel, decahydroquinoline may be obtained. Likewise gtetn- 
aldine furnishes decahydroquinaldine in excellent yield.^'* 

489. By hydrogenating quinoline at a higher temperature, the 
normal addition of hydrogen does not take place, but the ring is 
opened to yield ethyUo.tolvidine, which does not remain as such but 
closes the ring, with loss of hydrogen to givea-methyl-indol: ^** 

118 Bbbtsau, CompL rend,, 140, 942 (1005). 

^^* Schmidt and Mbtzobr, Berichte, 40, 4240 (1007). 

^^7 Padoa and Fabbib, Gcui, Chvm, Ital., 39 (1), 333 (1900). 

"• Padoa, Gaz. Ckim, Ital,, 36 (2), 317 (1006). 

^^* Sabatibb and Mailhs, CompL rend,, Z44» 784 (1007). 

i«® DouBis, Compt. rend,, 157, 722 (1013). 

121 Padoa and Ponti, Lvncei, 15 (2), 610 (1006), C, 1907 (D, 570. 

"> Dabzbns, Compt. rend,, 149, 1001 (1000). 

^3* Sabatieb and Mubat, Compt. rend., 158, 300 (1014). 

^ Padoa and Cabughi, Lincei, 15, 113 (1006), C, 1906 (2), 1011. 



O.CH, 



176 HYDROGENATIONS IN THE GAS PHASE 493 

CH CH CH CH 

HC C CH HC C.CH, HC C — CH 

HC C CH~*HC C.NH.CH, ~* HC C C.CH, 

490. Carbazol, dipheivyl'iinide, when hydrogenated over nickel at 
200^ under 10 atmoBpherea pressure, gives aj3-dimethyl-indol: ^'' 

HCT \; Cr ^CH HCT Nj 

491. Acridine is slowly hydrogenated over nickel at 250-270° to 
afi-dimethyUquinoUne: ^** 

HC^ \/|">C^ \)H HC \/ "^C.CHi 

°^Vh AAh/*\ch/^ ° Vh/'^Nch/ '""^ 

9. Carbon Disulphide 

492. When carbon disulphide vapors are carried by an excess of 
hydrogen over nickel at 180^, a volatile, extremely ill-smelling sub- 
stance is produced which gives a yellow mercury salt, a white cad- 
mium salt, and brown lead and copper salts, and which appears to be 
methylene'dithiol, HjC(SH),."^ 

HyDBOQBNATIONS with DECOMPOSmONS 

493. Catalytic nickel quite frequently exercises a more or less 
intense decomposing action on the molecules: in such cases not only 
the orignal compound but also the fragments resulting from its 
decomposition are hydrogenated. 

Hydrocarbons. We shall study in Chapter XXI the decom- 
positions that hydrocarbons undergo at high temperatures in the 
presence of nickel and other catalysts. The study of the simultaneous 
hydrogenations can not be separated from that of the decompositions 
and molecular condensations resulting therefrom. 

»« Padoa and Chiaiw, lAncei, z6 (2), 762 (1007), C, 2908 (1), 640. 
^s< Padoa and Fabbib, Lincei, z6 (1), 021 (1007), C, 1907 (2), 612. 
"7 Sabactb and Espu^ BuU. Soc. Chim. (4), 25, 22S (1014). 



491 CATALYSIS IN ORGANIC CHEMISTRY 176 

4d4. Aliphatic and Aromatic Ethers. Aliphatic ethers resist 
hydrogenation over nickel quite well, but when it is carried out above 
250°, there is decomposition into hydrocarbon and alcohol which is 
then attacked, furnishing the products of the hydrogenation of its 
debris. 

Thus ethyl ether g^ves ethane and alcohol which gives the frag- 
ments of acetaldehyde, of which the carbon monoxide is partly 
changed to methane: ^'' 

(C,H,),0 + H, — CA + CHa . CH,OH 
then CH, . CH.OH — CH^ + CO + H, 

CO + 3H, — CH^ + H,0. 

Aromatic ethers undergo an analogous decomposition with nickel, 
this taking place at moderate temperatures with the mixed alkyl 
phenyl ethers and greatly diminishing the yields of the mixed alkyl" 
cyclo^Uphatic ethers which are made by their hydrogenation. 

In the hydrogenation of anisol to methoxy-cyclohexane (464), 
there is the production of certain amounts of methyl alcohol and 
cyclohexane}*^ If the operation is carried on above 300°, there is no 
hydrogenation of the nucleus and scission is rapid in the same 
manner as with aliphatic ethers. 

We have two reactions: 

C^He . . R + H, — RH + CeH, . OH 

phenol 

and CeH, . O . R + H[, — CeHe + R . OH 

•loohol 

the alcohol itself being more or less broken down by the hydrogena- 
tion. 

This is the case with the methyl ethers of phenol, of the three 
cresols, ot a-naphthol, etc., and also with phenyl oxide which is the 
most resistant to decomposition.^** 

495. Phenyl Isocyanate. Phenyl isocyanate, when hydrogenated 
over nickel at 190°, breaks up into two portions which are hydro- 
genated separately: 

CeH, .N : CO — CO + CeH^ .N-. 

We obtain aniline and carbon monoxide which yields methane 
with the formation of water. This reacts quantitatively with the 
original compound to give carbon dioxide and solid diphenyl-urea}^^ 

^*s Sabatibr and Skndebbns, BvU. 8oc, Chim. (3), 33> 616 (1905). 
»» Mau^hs and Mubat, BvU. Sac. CHm. (4), xz, 122 (1912). 
^*<^ Sabatieb and Mau^hs, Compt. rend,, 144, 825 (1907). 



177 HYDROGENATIONS IN THE GAS PHASE 497 

496. Amines. Various amines bydrogenated over nickel at above 
300-^50^, tend to form ammoma and a hydrocarbon. This reaction 
which takes place readily with aliphatic amines has abready been 
mentioned with anUine (378). It takes place with the homologs of 
aniline, with benzyl-^imine and with the ruiphthyl<Lmine8. 

Hexamethylene'tetramine is completely decomposed yielding 
ammonia^ trimethyUamine and methane: ^^^ 

N(CH, . N : CH,), + 9H, — N(CH,), + 3NH, + 3CH,. 

497. Compounds Containing -N . N-. PhenyUiydrasme, bydro- 
genated above 210^, is split into ammotda and anilme, accompanied 
by cydohexyl-^^mine, dicyclohexyl-amine, and even by benzene and 
cyclohexane}^ 

The main reaction is: 

CeH, . NH . NH, + H, — NH, + CeH, . NH,. 

Azobemene, CeH. . N : N . CeH., bydrogenated at 290**, yields 
amline chiefly.^'* 

Indol. On hydrogenation over nickel at 200^, indol is split into 
o.toluidine and methane: "' 






Cja/ ^CH + 3H, - CH/ + CH4 



iM Gbasu, Gom. Chim. lUd., 36 (2), SOS (1906). 

1** SABAxm and SurnsiNB, Butt. 80c. Chim. (3), 35, 2S9 (1006). 

i«t Cabbasoo and P/mul, Lincei, 14 (2), 9M (1906). C, 1906 (2), 683. 



CHAPTER X 

HYDROGENATIONS (Continued) 

HYDROGENATIONS IN GASEOUS SYSTEM (Continued) 

I. — USE OP VARIOUS CATALYSTS 

498. Nickel as a hydrogenation catalyst can be replaced by vari- 
ous finely divided metals, such as cobalt, iron, copper, platinum, and 
the platinum metals, particularly palladium. 

Cobalt 

499. Finely divided cobalt such as is produced by the reduction 
of the oxide in the hydrogenation tube itself, seems to be able to take 
the place of nickel in all the various reactions which nickel can 
catalyze. 

But its use is disadvantageous because its activity is less and more 
easily destroyed than that of nickel; because higher temperatures 
are required when using it ; and also because the reduction of its oxide 
is practicable only in the neighborhood of 400^, and hence the oxide 
resulting from spontaneous oxidation during the time the apparatus 
is cold and out of use, can not be reduced at temperatures below 250^ 
such as are commonly used in hydrogenations. 

500. Ethylene Hydrocarbons. When a mixture of ethylene and 
an excess of hydrogen is passed over cold reduced cobalt, immediate 
action takes place with the production of ethane, and the end of the 
cobalt layer becomes hot. The heated portion moves slowly along 
the metal and the evolution of heat finally ceases and the production 
of ethane stops also, doubtless because the cobalt is slightly car- 
bonized in the course of the reaction and its activity so diminished 
that it is unable to continue the reaction without the aid of external 
heat. 

At 150^, the hydrogenation of ethylene continues indefinitely, 
but the cobalt is slowly weakened, more rapidly than nickel. 

Above 300°, the disturbance due to, the action of the cobalt on 
the ethylene (910) appears and the issuing gases contain methane 
and carry along small amounts of liquid hydrocarbons.^ 

^ Sabatodb and Bbndbbbnb, Arm, Ckim. Phya. (8), 4, 344 (1900 • 

178 



179 HYDROGENATIONS IN GASEOUS SYSTEM 606 

The action of cobalt on the homologs of ethylene is similar to 
that of nickel but weaker. 

601. Acetylene. Reduced cobalt, entirely free from nickel, can 
serve to hydrogenate acetylene, but there is no reaction in the cold. 
The fixation of hydrogen be^ns at about ISO'', and the ethane pro- 
duced is accompanied by a small amount of liquid hydrocarbons, 
which are more abundant if the reaction is carried on at 260°.' 

602. Ben2ene and its Homologs. Reduced cobalt can effect the 
direct hydrogenation of benzene and its homologs at 180°, but its 
activity falls off rather rapidly .• 

603. Aliphatic Aldehydes and Ketones. Cobalt can transform 
aliphatic aldehydes and ketones into the alcohols below 180°, but is 
less active than nickel. Under identical conditions, with the same 
apparatus, the same temperature, the same velocity of hydrogen, and 
the same rate of admission of acetone, the ^ yield of iaopropyl alcohol 
was about 83% with nickel as catalyst but slightly less than 60% 
with cobalt.* 

604. Carbon Monoxide and Dioxide. Reduced cobalt can cause 
the transformation of carbon monoxide into methane, as does nickel, 
but the reaction does not begin till about 270°. It is rapid at 300°, 
but is opposed more strongly, than is the case with nickel, by the 
decomposition of carbon monoxide into carbon and the dioxide (616) . 
This decomposition is as rapid with cobalt as with nickel, while the 
hydrogenation is slower with the cobalt. 

The hydrogenation of carbon dioxide is effected by cobalt from 
300° up. It is rapid at 360° and even more so at 400° and is accom- 
plished without any complications.* 

Iron 

606. Finely divided iron, obtained by the reduction of its oxides, 
can be substituted for nickel as a hydrogenation catalyst in certain 
cases, but is less active than nickel and even less active than cobalt. 
Besides, it has the marked disadvantage of being much more difSicult 
to prepare from its oxide. Between 400 and 600° it is necessary to 
continue the action of hydrogen from six to seven hours to obtain 
complete reduction. When the metal is reduced more rapidly at 
higher temperatures, it is no longer pyrophoric and has only sli^t 
activity. 

* SABATxaa and Sbndebbns, Ann, Chim. Phys. (8), 4, 352 (1905). 
> Sabatixb and Sendbbjbns, Ann, Chim, Phps. (8), 4, 368 (1905). 

« Sabatixb and Sbndbbbnb, Ann, Chim. Phya, (8), 4, 400 and 403 (1905). 

* Sabatixb and Siiin>BBXNB, Ann, Chim. PhyB. (8), 4, 424 (1905). 



1(06 CATALYSIS IN ORGANIC CHEMISTRY 180 

506. Ethylene Hydrocarbons. Iron causes the hydrogenation 
of ethylene only above 180**, and its activity decreases with the slow 
carbonizing of the metal. 

Acetylene. The hydrogenation of acetylene does not commence 
till above 180^, and always gives rise to the formation of rather large 
amounts of colored hydrocarbons, containing higher ethylene hydro- 
carbons soluble in sulphuric acid, aromatic hydrocarbons, and only 
a small amoimt of saturated hydrocarbons. The odor and appearance 
of the product suggest certain natural petroleums of Canada. 

To a certain extent, iron can cause the hydrogenation of aldehydes, 
ketones and nitro compounds, but is incapable of transforming carbon 
monoxide and dioxide into msthane or of adding hydrogen to the 
benzene nucleus,^ 

Copper 

607. Reduced copper is a useful catalyst for certain hydrogena- 
tions. For such its use is advantageous on account of its ease of 
preparation, the low temperature, below 180°, at which its oxide can 
be reduced, and its resistance to poisons which is more marked than 
with other metal catalysts. 

508. Reduction of Carbon Dioxide. Copper, even in its most 
active form (59) , is incapable of causing the direct hydrogenation of 
carbon monoxide to methane and does not show any action on mix- 
tures of carbon monoxide and hydrogen below 450°. 

It is the same way with mixtures of hydrogen and carbon dioxide 
below 300°, but between 350 and 400° a special reaction appears 
gradually and is quite definite at 420-450°. There is reduction of 
the carbon dioxide into carbon monoxide and water, according to the 
equation: 

CO, + H, — CO + H,0. 

Thus with a mixture of one part carbon dioxide to about three 
parts of hydrogen, a gas was obtained containing: 

Carbon monoxide 10.0% by volume 

Carbon dioxide 17.2% " 



Hydrogen 72.8% 



'O 



(t It 



More than a third of the carbon dioxide had been reduced to the 
monoxide. The proportion reduced is less when the concentration of 
hydrogen in the mixture is less. 

• Sabahbb and Sundbbinb. Ann, Chim. Phys. (8), 4, 346, 353, 368» 426, and 
428 (1900. 



181 HYDROGENATIONS IN GASEOUS SYSTEM S12 

In no case is even a trace of methane formed.^ 

509. Nitre Compounds. Copper gives results analogous to those 
with nickel (373 to 378) only at higher temperatures. 

Nitrous oxide is reduced to nitrogen at 180^ and nitric oxide 
is changed into ammonia at the same temperature. Nitrogen 
peroxide givfes copper nitride in the cold,* and it is only towards 
180^ that ammonia is produced. If the proportion of nitrogen per- 
oxide becomes too great, there is incandescence followed by an ex- 
plosion.* 

510. Nitromethane, hydrogenated between 300 and 400^, gives, 
along with methyl-amine, a liquid of a more or less brown color with 
a disgusting odor in which appear crystals which are the methyl- 
aminesalt of nitromethane. 

Between 300 and 400^, nitromethane gives ethyUamine without 
notable complications.^* 

511. Copper is the best of all the finely divided metals for trans- 
forming aromatic nitro derivatives into the amines, since its very 
regular hydrogenating action affects only the -NO, group and does 
not touch the aromatic nucleus. Nitrobenzene is thus changed to 
aniline from 230^ up, the reaction being rapid and very regular be- 
tween 300 and 400°, and so long as the hydrogen is in excess, aniline 
is obtained in 98% yield containing only traces of nitrobenzene and 
the red asobenzene. The same metal can be used for a long time. 
The hydrogen can, without inconvenience, be replaced by water gas, 
the carbon monoxide of which acts usefully as a reducing agent to 
some extent since a part of it is transformed into carbon dioxide. 
The manufacture carried out with copper, a metal which is not costly 
and which serves for a long time and is easily regenerated without 
loss, and by means of a very cheap gas, can be carried on continu- 
ously and is very economical.^^ 

Coppered pumice at 200-210° has been proposed as a substitute 
for copper.** 

612. The manufacture of the toluidines from the nitrotoluenes is 
also advantageously carried on by copper at 300-400°, and likewise 

^ Sabatodb and Sbndbbknb, Ann. Chvm. Phys. (8), 4, 426 (1906). 

* Sabatibb and Sbndbbbnb, Ann. Chim. Phya, (7), 7, 401 (1S96). 

* Sabatibb and Sbndbbbnb, CompL rend.^ 135, 278 (1902). 
^* Sabatibb and Sbndbbbnb, Ccmpi. rend., 135, 227 (1902). 

u Sabatibb and Sbndbbbnb, Compt. rmuLf Z33» 321 (1901). — Sabatubb, Vth. 
Cong. Purs and AppL Chem., BerUn, 1903, 11, 617. — Sbndbbbnb, Frsneh PaUnt, 
312,615 (1901). 

» Badibchb, BnuUsh ptUeni. 6,409 of 1915. — /. Soe. Chrnn. Ind., 35, 920 
(1916). 



SIS CATALYSIS IN ORGANIC CHEMISTRY 182 

a-^napMhyl^LTmne is readily obtained from a-rdtronaphthdlene at 
330-^50**." 

The chlofTiitrohenzenes are regularly transformed by copper into 
the chloraniUnes at 360-^380°. On the contrary, copper gives poor 
results with the dinitrobertzenes and the bromndtrobenzenes}^ 

At 265^ the results are excellent with the nitrophenoh and the 
nitraniimes}^ 

613. Esters of Nitrous Acid. Nitrous esters are regularly 
hydrogenated into the amines, over copper as well as over nickel, but 
at a higher temperature, 330-^50?, the results are satisfactory for 
nitrites with heavy hydrocarbon chains, but are less so for methyl 
fdtrite which gives brown products analogous to those obtained from 
nitromethane.^* 

514. Oximes. Copper accomplishes the regular hydrogenation of 
aliphatic aldoximes and ketoximes between 200 and 300° into primary 
and secondary amines without complications,^^ and the same may be 
said about aliphatic amides}^ 

616. Ethylene Compounds. Most often copper serves to add 
hydrogen to the ethylene double bond. 

Ethylene, propylene and a-octene are changed to the correspond- 
ing saturated compounds at above 180°. However, trvmethyU 
ethylene and fi-hexene are not hydrogenated by copper, and it has 
been concluded that copper does not cause the hydrogenation of any 
except a-ethylene compounds, that is to say, those in which one of 
the CHs groups of the ethylene is not substituted.^* 

This limitation is not general since the vapors of oleic acid are 
readily hydrogenated into stearic acid at around 300°. Water gas 
can be substituted for the piu'e hydrogen in this preparation and it 
has industrial possibilities.'^ 

It may be noted that copper does not cause the hydrogenation of 
symmetrical diphenylethylene, or stObene, CeH, . CH : CH . CeH,, of 
cyclohexene, CgHio, or of the msthyUcyclohexenes.*^ 

516. The use of copper, which acts on the ethylene double bond 

" Sabatibb and Sendbbbns, Campi. rend., 135, 225 (1902). 
i« MiONONAC, BuU. Soc Chim,, (4), 7, 154, 270 and 504 (1910). 
" Bbown and Cabbick, /. Amer. Chem, 8oe,, 41, 436 (1919). . 
1* Gaxtdion, Ann, Chim. Phys, (8), 25, 136 (1912). 
1' Mailhb, Compt, rend,, 140, 1691 (1905) and 141, 113 (1905). 
u Mah^hb, BuU, 80c. Chim. (3), 35, 614 (1906). 
^* Sabatibb and Sbndbbbns, Compt, rend., 134, 1127 (1902). 
*^ Sabatibb, French pcOerU, 394,957 (1907). 

^ Sabatibb, SOlh. Cong, dea 80c 8av. (1912). Jaum. Offic., 3628: April 11, 
1912. 



183 HYDROGENATIONS IN GASEOUS SYSTEM 621 

without attacking the aromatic nucleus, permits us to effect certain 
hydrogenations distinct from those obtained with nickel. Phenyl' 
ethylene, or styrene, CeH^ . CH : CH2, which nickel changes into 
ethyUcyclohexane, is transformed quantitatively at 180^ by copper 
into ethyl-benzene?^ 

617. Limonene, CHj.CeHg.C/^ which nickel readily 

\CH, 

changes into menthane (477), gives only dihydroUmonene, C^oHisy 
isomeric with menthene?^ 

518. Acetylene Hydrocarbons. Copper can not hydrogenate 
acetylene in the cold, the reaction being aroimd 130^ over copper 
with a light purple color and aroimd 180^ over copper of a clear red. 
Carried on with excess of hydrogen, the reaction always gives a cer- 
tain proportion of liquid hydrocarbons along with the ethane. 

When the amount of acetylene equals or surpasses the amoimt of 
hydrogen, the special condensing action of copper on acetylene (914) 
becomes evident: the copper swells up gradually on account of 
the formation of solid cuprene, (C^He)! the gases evolved contain 
higher ethylene hydrocarbons and a mixtiu'e of liquid ethylene and 
aromatic hydrocarbons (benzene, and homologs and styrene) is col- 
lected. 

A gas mixture containing 21 H2 to 19 CgHg gave, at 160^ over 
violet copper, a condensation of materials containing 25 C with about 
65% carbon, one third as cuprene and the other two thirds as liquid 
hydrocarbons." 

519. The hydrogenation of a-heptine over copper at below 200®, 
gave a little heptane, but chiefly heptene, diheptene, and triheptene?^ 

520. Phenyl acetylene, CJS.^ . C ; CH, which nickel transforms 
easily into ethyl-cyclohexane (451), gave by hydrogenation over 
copper between 190 and 250'', ethyUbenzene, CeH, . CH, . CHg, 
accompanied by a little phenyl-ethylene and a nearly equal amoimt 
of symmetrical diphenyl-butane, C0H9 . CH, . CH, . CH, . CH, . CeH., 
a well crystallized solid.*' 

621. Nitriles. Copper can transform nitriles into primary and 
secondary amines'* in the same manner that nickel does. It acts 

" Sabatibb and SaNDBBmrs, Compt, rend,, 133, 1265 (1901). 
" Sabatibb and Sbndbbbms, CompL rend., 130, 1559 (1900). 
^ Sabatibb and Sbmdbbbns, CompL rend., 135, 87 (1902). 
* Sabatibb and Sbmdbbbns, Compt. rend., las, 88 (1902). 
*• Sabatibb and Sbnbbbbnb, Compt. rend., 140, 482 (1905) and Bull. 8oe. 
Chim. (3), 33, 371 (1905). 



622 CATALYSIS IN ORGANIC CHEMISTRY 184 

similarly on the carbyUamines,*^ but its action is less rapid than that 
of nickel. 

522. Aliphatic Aldehydes and Ketones. Below 200^, copper 
can transform these slowly into the alcohols, but the inverse action 
usually preponderates and this makes the use of copper less 
advantageous. 

Furthermore, copper is incapable of transforming the oxides of 
carbon into methane or of hydrogenating the aromatic nucleus. 

523. Aromatic Ketones. When benzophenone is hydrogenated 
at 360*^ over copper with a violet tint, prepared by the reduction of 
the hydroxide (59), diphenyl-methane is formed directly.** 

Platinum 

624. Platinum black can be used for direct hydrogenation in quite 
a large number of cases and its activity is greater than that of copper 
though less t^an that of nickel. Its activity is greater, the more 
tenuous the black and the more recently it has been prepared. It is 
rapidly exhausted and this fact taken together with the high cost of 
the metal renders its use generally less advantageous. 

Platinum moss, or sponge, behaves the same way but with less 
activity, which is usually not manifested except at a higher tempera- 
ture. 

525. Union of Carbon and Hydrogen. The presence of finely 
divided platinum on the carbon accelerates its direct combination 
with hydrogen to form msthane at 1200^, the limit of the combina- 
tion, 0.53%, not being altered.** 

526. Ethylene Compounds. A mixture of ethylene and hydrogen 
is transformed into ethane in the cold in the presence of platinum 
black.'® But after some time the slight carbonization of the metal 
prevents the reaction from proceeding at the ordinary temperature 
and it is necessary to heat to 120^, or even to 180^, to obtain a rapid 
formation of ethane.*^ 

Analogous results are obtained with propylene. 
The vapors of amyl oleate can be hydrogenated over platinized 
asbestos to amyl stearate.*^ 

527. Acetylene Hydrocarbons. Acetylene combines with hydro- 

^ Sabatibb and Mailhb, Ann. Chim. Phys., (S) i6y 95 (1909). 

* Sabatibb and Mubat, Compl. rend,, 158, 761 (1914). 

*• Fung, J. Chem. Soe., 97, 498 (1910). 

•• YON WnJ>B, BerichU, 7, 352 (1874). 

"^ Sabatibb and Sbndbbbns, Compi. rend,, 131, 40 (1900). 

*> FouN, /. Russian Phys. Chem. Soe., 38, 419 (1906), C, 1906 (2), 758. 



185 HYDR0GENATI0N8 IN GASEOUS SYSTEM 638 

gen in the cold in the presence of platinum black, giving first ethylene 
and then ethane.*® 

In presence of an excess of hydrogen, acetylene is entirely trans- 
formed into pure ethane without any side reactions. 

At 180^ the same reaction takes place more rapidly but there is 
the formation of a certain amoimt of higher liquid hydrocarbons. 
By augmenting the proportion of acetylene in the mixture, ethylene 
becomes the main product but some ethane is always formed even 
though unchanged acetylene remains. 

If the proportion of acetylene becomes great enough, with the 
platinum black at 180^, a certain amount of smoky decomposition 
of the gas is observed and this ends with incandescence, as is the case 
with nickel (914). 

Platinum sponge is not active in the cold and does not effect the 
hydrogenation of acetylene except above 180®." 

628. Hydrocyanic Acid. Platinum black can hydrogenate 
hydrocyanic acid to methyUtmine at 116®, but the cyanidation of the 
metal soon diminishes its activity and stops the reaction."^ 

529. Nitro Compounds. Nitrogen oxides, either nitric oxide or 
the dioxide, are readily reduced to ammonia with the aid of platinum 
sponge which is thereby heated to incandescence.** 

530. Nitromsthane is hydrogenated over platinum sponge at 300®, 
more slowly than over copper but with analogous results (510) .** 

531. Various forms of platinum, black, sponge, and platinized 
asbestos, can cause the transformation of nitrobenzene into aniline, 
but their catalytic power is low and, if the hydrogen is not in large 
excess, there is incomplete reduction with the formation of crystal- 
lized hydrazobenzene.*^ 

532. Aliphatic Aldehydes and Ketones. Finely divided plati- 
num is unsuitable for the regular transformation of these into the 
alcohols, since at the temperatures which must be used, which are 
above 200®, the metal acts powerfully to break up the aldehyde mole- 
cule into carbon monoxide and hydrocarbon (622). 

533. Finely divided platinum, even in the form of highly active 
black, has proved powerless to effect the direct hydrogenation of 
carbon monoxide or dioxide to methane. There is no action even up 
to 450®.** 

** Babatibb and SsMDimaNS, CcmpL rend., 131, 40 (1900). 

•« Dbbus, J. Chmn. Soc., x6» 249 (1863). 

** KuHUiANK, Ccmpi, rend,, 7* 1107 (1838). ' 

** Babatisb and Shndbbxns, Ccmpi, rend., 135, 226 (1902). 

*' Sabatub and Sbmdbbxnb, Ann. Chim. Phye. (8), 4, 414 (1906). 

* Sabatobs and Sbmdbbxnb, Compt. rend., 134, 514 and 689 (1902). 



634 CATALYSIS IN ORGANIC CHEMISTRY 186 

534. Aromatic Nucleus. Recently prepared platinum black can 
transform benzene into cyclohexane at 180^ for a time, but its ac- 
tivity diminishes rapidly and soon disappears. 

Platinum sponge has not this power.*^ 

According to Zelinsky, platinum is as well able to hydrogenate 
benzene, toluene, the three xylenes and ethyl-benzene, as is nickel.^^ 

He states the same about palladium. 

635. Polymethylene Rings. SpirocycUme, with the aid of plati- 
num, first adds H, to form ethyl trimethylene, which passes to pen- 
tane by a second addition: ^^ 



CH2\ yCHj CHjx^ 
CH,/ \CH, CH,/ 



XX • — > • ^CH . CMsCHj — ► CHj . CHj . CHs • CHj . CHs* 



Cyclo-octatetrene adds 4H2 with the aid of platinum sponge to 
form cydooctane}^ 

Palladium 

536. Palladium, previously charged with hydrogen, is able to effect 
varied hydrogenations, such as the transformation of nitrobenzene into 
aniline, nitromethane into methyl-amine, and nitrophenols into amino- 
phenols (Graham) . It is easy to foresee that it can serve equally well 
as a hydrogenation catalyst, the intermediate hydride which enables 
it to accomplish these results being notably stable in this case. 

The formation of aniline by the action of hydrogen on nitrobenzene 
in the presence of palladium was shown by Saytzeff.^* 

Carbon monoxide can be reduced in the cold, or better, at 400^, 
to methane in the presence of palladium sponge.^ 

Phenanthrene, carried over palladium sponge at 150-160^ by a 
current of hydrogen, gives a mixture of tetrahydro- and octohydro- 
phenanthrene.^ 

Unfortimately the excessive price of palladium restricts its useful 
applications. 

** Sabatibb and SoNDBBaNS, Ann, Chim. Phya, (8), 4, 368 (1905). 

«« Zbunskt, J. Russian Phys. Chmn. Soc^ 44, 274 (1912). 

^ Zbunskt, J, Russian Phys, Chem. 8oe,, 44, 275 (1912). 

^ WiLLSTiLTTBB and Wasbb, Berichte, 44, 3423 (1911). 

« EoLBB and Sattzbff, J, praJU. Chem. (2), 4, 418 (1871). 

^ Bbbtbau, Eiuds sur les fndh. dP hydrogenation, I9II4 p. 22. 

^ Bbbtbau, Ihid., p. 24. 



187 HYDROGENATIONS IN GASEOUS SYSTEM 838 

IL — HYDROGENATION BY NASCENT HYDROGEN 

537. Certain catalyses yield hydrogen and the gas so produced 
can be immediately employed for hydrogenation purposes. We can 
thus use as sources of active hydrogen, alcclihol vapors, formic add, 
and even a mixture of water and carbon monoxide. 

Hydrogenation by Alcohol Vapors 

638. Primary and secondary alcohols can, under the influence of 
various catalysts, be decomposed into aldehydes and ketones and 
hydrogen (653) : the hydrogen thus set free can act in the nascent 
state on substances the vapors of which are mixed with the alcohols. 

Copper can easily realize such reactions, but we can attribute to 
its action the hydrogenation correlative to the decomposition. 

We can use mixed oxide catalysts (676) and even dehydrating 
catalysts, such as thoria, the presence of the substance that can be 
hydrogenated orienting the decomposition of the alcohol in the direc- 
tion of the separation of hydrogen and greatly diminishing the extent 
of the dehydration reaction. 

Thus over thoria at 420^, benzhydrol, with ethyl alcohol in excess, 
gives much diphenyl-methane accompanied by a little benzophenone 
and tetraphenyl-ethane (720) : acetaldehyde is evolved and the gases 
arising from its decomposition. 

The alcohol most suitable for this sort of hydrogenation is methyl 
alcohol on account of its great tendency to produce formaldehyde 
and particularly the products of its decomposition, carbon monoxide 
and hydrogen (693) : 

H . CH,OH — 2H, + CO. 

The vapors of the substance to be hydrogenated are passed over 
thoria at 420^, with an excess of methyl alcohol, the hydrogenation 
is advantageously accomplished in all cases in which the product is 
stable at that temperature. Thus hemopheru)ne and benzhydrol are 
changed almost completely into diphenyl-methane, while benzyl al- 
cohol and benzaldehyde give toluene, acetopherume furnishes ethyl- 
benzene, and nitrobenzene yields anUine.^^*'' 

^ Sabatddb and Muiut, Campi. rend., 157, 1499 (1913). — BuO, 8oe, Chim. 
(4), 15, 227 (1914). 

*'' By using 2.5 moles of ethyl alcohol to 1 of bensaldehyde, and paadog the 
mixed vapors over ceria on asbestos at SOO-dOO**, bensyl alcohol is obtained 
along with acetaldehyde. Similarly citronellol is formed from citronellal and 
pbenylethyl alcohol from phenylacetaldehyde. The yields are variable and the 
catalyst is rapidly fouled, prol^bly on account of the formation of condensation 
products of the aldehydes either alone or with, each other. See article by 
Milligan and^myself, Jawr. Atner, Chem. 8oe., 44, 202 (1922). — E. E. R. 



639 CATALYSIS IN ORGANIC CHEMISTRY 188 



Hydrogenation by the Vapors of Formic Acid 

539. The vapors of formic add passing over various catalysts, 
finely divided platinum, copper or nickel reduced from their oxides, 
cadmium, stannous oxide or zinc oxide, are decomposed below 300® 
into carbon dioxide and hydrogen (824) : 

HCO^H - H, + CO,. 

This hydrogen can be used to hydrogenate substances the vapors 
of which are present in the system. Under these conditions, using 
nickel at 300®, acetaphenone is changed to ethyl-bemene, phenyU 
ethyUkeione into propyl-bemene, and benzophenone into diphenyl-' 
methane. 

Thofia, alumina and zirconia effect the same hydrogenations above 
300®, but the oxides of manganese appear to be inactive.^* 

Hydrogenation by the Mixture of Carbon Monoxide and Water 

640. The mixture CO + H^O can be transformed into CO, + H,, 
the reaction being favored by the temporary combination of the car- 
bon dioxide with the catalyst or by the immediate utilization, thanks 
to the catalyst, of the hydrogen to hydrogenate the carbon monoxide 
into methane. The reaction then becomes: 

4C0 + 2H,0 — SCO, + CH,. 

It is found, in fact, that a mixture of steam and carbon monoxide 
passing over lime at above 1000® gives the above reaction and we 
have the following reaction at the same time: 

CO + H^O — CO, + H,. 

As calcium carbonate is entirely decomposed at this temperature, 
the lime acts as a true catalyst. By separating the carbon dioxide, 
we can obtain a mixture containing: 

Hydrogen 88% by volume 

Methane** 12% 

The same mixture passing over iron wool likewise gives methane 
in varying amoimts: 

At 260® 7.3% by volume 

At 960® 115% 

At 1260® 7.1% 

By the use of fine nickel turnings a maximum content of 12.6% of 

«• MaUiHB and de Godon, BuU, 8oe, Ckim, (4),'''ai, 61 (1917). 
«* ViGNON, Campi., rend,, Z56» 1995 (1913). 



I 



189 HYDROQENATIONS IN GASEOUS SYSTEM 640 

methane is obtained at 400^. With copper turnings, almost no result 

is obtained at 5W, and the maximum, 6.3%, is obtained at 700^. I 

Precipitated nlica gives a maximum of 8.4% at 700^, while for 
aJumina, obtained by calcining the hydroxide, the maximum, 3.8%, ! 

is obtained at 950^, and for magnesia, a maximum of 6.7% at 900^. "^ 

'^ ViONON, Cimpl, rend,, 157, 131 (1013). — BvU, Soe. Chim. (4), Z3» 889 (1913). 



CHAPTER XI 

HYDROGENATIONS (Continued) 

DIRECT HYDROGENATIONS OF LIQUIDS IN 
CONTACT WITH METAL CATALYSTS 

541. We have explained the phenomena of direct hydrogenation 
as accomplished by various finely divided metals when the substance 
to be hydrogenated is brought in contact with the metal in the gaseous 
form, by assuming a sort of hydride of the metal, an unstable com- 
pound formed rapidly and decomposed rapidly in the act of hydro- 
genating the substance (165). This explanation does not necessarily 
require that the substance to be hydrogenated be in the gaseous form 
as we can see that the same reaction can be accomplished with a 
liquid material intimately mixed with a finely divided metal capable 
of taking up hydrogen. In order that the hydrogen may come into 
contact with the metal it is necessary that its solubility in the liquid 
be made sufficiently great by using low temperatures at the ordinary 
pressure, or a high pressiure of hydrogen if it is necessary to heat. 

An energetic and continuous agitation, constantly renewing the 
contact of the catalyst with the unchanged portions of the liquid will 
be most useful. 

Furthermore, in order for the metal to be able to preserve its 
activity, it must not be oxidisable at the working temperature, or 
this temperature must be high enough to assure the reduction by the 
hydrogen in the system of any oxide formed. 

542. From these conditions may be derived several methods which 
give results in general identical with those obtained by the method 
of Sabatier and Senderens of hydrogenating vapors over nickel, and 
which may offer great advantages in some cases. 

The first attempt to hydrogenate substances directly in the liquid 
state had for its object the hydrogenation of liquid fats and was made 
in 1902-1903.^ Then followed the method of Ipatief based on the use 
of nickel at 250 to 400^ in the presence of hydrogen compressed to 
more than 100 atmospheres, and at almost the same time the method 

^ liBPBmcB and Sibvkb, German patent, 141,029 (1903). — Nobman, English 
patent, 1515 of 1903. Chem. Cent., 1903 (1), 1199. 

190 



191 DIBEC3T HYDROGENATIONS OF LIQUIDS 646 

of Paal, relying on the use of colloidal metals (platinum or palladium) 
acting at near the ordinary temperature, and then in 1908, the metiiod 
of Willstatter which depends on the use of platinum black. 

We shall take up first the methods using the precious metals, then 
those employing the conmion metals whether at high pressures of 
hydrogen or at pressures near the atmospheric. 

543. Except the process of Ipatief, which, on accoimt of the high 
pressures used, demands an entirely special outfit, the various methods 
of hydrogenation in liquid medium employ apparatus of the same 
kind, though they may vary much in forms and dimensions. The 
main thing is a working vessel containing the liquid to be hydro- 
genated, either alone or dissolved in a suitable solvent and mixed 
with the solid catalyst. This recipient, which must be capable of 
being kept at known temperatures, is mounted on a mechanical shaker 
capable of assuring the best possible contact between liquid, catalyzer, 
and hydrogen. It is kept in communication with a cylinder of com- 
pressed hydrogen which can be introduced from time to time imder 
known pressures, or if the hydrogenation is to be carried on at 
atmospheric pressure, the recipient commimicates continuously with 
a hydrogen gascmieter, the graduations of which enable us to follow 
the course of the reaction and to determine its end. 

I. — METHOD OF PAAL 

544. The methods of preparing colloidal platinum and palladium, 
such as are used in the method of Paal, have been given above (67 to 
71). The amoimts of these metals to be used are not over 16 to 50% 
of the weight of the substance to be hydrogenated, and can, according 
to Paal, be reduced to from 0.5 to 1% for colloidal palladium or to 
1 to 2% for colloidal platinum.^ 

Use of Colloidal Palladium 

545. Reductions with Simultaneous Fixation of Hydrogen. 
Nitro compoimds are readily changed into amino compounds. Thus 
nitrobemene is easily transformed into amUne, particularly at 65- 
85^.* 

Nitroacetophenone gives aminoa/^tophenone.^ 
The halogen of chlorine or bromine derivatives may be readily 
replaced by hydrogen when a current of hydrogen is passed through 

> Paal, German paUrU, 298,193, 1013, — Chem. Cent,, 19x7 (2), 145. 
* Paal and AMBBBasB, Berichte, 38, 1406 (1906). 
« Sktta and Mjbtbb, BeridUe, 45, 3579 (1912). 



646 CATALYSIS IN ORGANIC CHEMISTRY 192 

the compound containing colloidal palladium and boiling under reflux. 
Thus we obtain benzene from brombenzene. This reduction works 
well with o.chlor'benz(nc add, o.chl(>rcinnannc add, chlorcrotomc 
add, and chlorcaffdne, etc., without any other change in the mole- 
cule.* 

646. Fixation of Hydrogen by Addition. The ethylene double 
bond is readily hydrogenated. 

Ethylene is easily transformed into ethane* 

Styrene gives ethyl-benzene. 

Bromstyrene is simultaneously saturated and dehalogenated to 
ethyl-benzeneJ 

1, lO^DiphenyUdecadiene (1,9) furnishes IflO-diphenyl-decane.* 

Mesityl oxide, treated in alcohol solution with the metal prepared 
by means of giun arabic, changes into methyl-iaobutyUketone* 

a-MethyUP-ethylrpropenal, hydrogenated imder the same condi- 
tions under 2 atmospheres pressure of hydrogen, gives chiefly the 
saturated aldehyde, a-methyUvaleric aldehyde, accompanied by a 
small amoimt of the unsaturated alcohol a-methyUpentenyl alcohol}* 

Crotonic, xsocrotonic, and tetrolic adds are transformed into the 
corresponding saturated acids.^^ 

Fumaric add in an hour and a half, and maldc add in seven hours 
are changed into atu^dnic add. Oldc add pves a 60% yield of 
stearic add in 43 minutes. 

Cinnamic add is changed into phenylpropionic add.^^ 

Cinnamic aldehyde, dissolved in 20 parts of alcohol, is transformed 
into phenylpropiomc aldehyde.^* 

Isopropylidene-cyclopentanone adds H, to form isopropyUcyclo^ 
pentanone: ** 

CHiv yCO -OH, CH,\ /CO- CH, 

>:!:CC 1 -* yCE.CW I 

CHs/ \CH,-CH, CH,/ ^CH,-CH, 

* RosBNMUND and Zbtbchb, Beridde, 51, 679 (1918). 

* Paal and Habticann, BerichU, 48, 984 (1915). 

' BoBSCEB and HxafBOBOBR, BeridUe, 48, 452 (1915). 

* BoHSCHB and Wollbmann, BerichU, 44, 3185 (1911). 

* Wallace, Nach. (?e». der Wiss. OoUingen, 1910, 517. — Sxita, BerichU, 48 
1486 (1915). 

'• Skita, BeridUe, 4B, 1486 (1915). 

^ BOasBKBN, VAN DBB WsTOB and Mom, Bee. Trav. Chim. Paife Bos., 35, 
260 (1915). 

u Paal and Gbrum, BerichU, 41, 2273 and 2277 (1908). 

>* Skita, Berithie, 48, 1691 (1915). — B5i»bksn, van dbr WBmB and Mom, 
Rec. Trap. Chim. Paye-Bae, 35, 260 (1916). 

M Wallace, Annalen, 394, 362 (1912). 



193 DIREC3T HYDROGENATIONS OF LIQUIDS 548 

547. In the case of diethylene compounds, if the double bonds are 
consecutive, both are hydrogenated simultaneously but if they are 
separated by more than one carbon atom, they are hydrogenated 
successively. 

Thus phorone gives first dihydrophorone and then valerone. 

DibenzyUdene-acetone, C^H^ . CH : CH . CO . CH : CH . CeHj, can 
give first bemyl-bemylidene-acetone, CJS.^ . CH : CH . CO . CH, .- 
CH, . CeHs, and then dibemyUaceione}^ 

548. The acetylene triple bond can be saturated in two steps. 
Acetylene itself gives ethylene chiefly, up to 80%.^* 

PhenyUacetylene in acetic acid solution gives styrene and then 
ethyl-benzene}'' 

Tolane yields stilbene and then dibenzyl, DiphenyUdiacetylene 
passes into ay -diphenyl-butadiene ay, then into ay-diphenyl-butane}'' 

Phenylpropiolic acid, CeHj . C : C . COOH, gives a poor yield of 
dnnamic acid, CeHg . CH : CH . CO J3., and does not go into phenyl- 
propionic.^* 

2,5-Dimethyl~hexine{3)-diol(2fi) adds only H, to give the 
ethylene-diol, and the same is true of l,4r-diphenyl''bvtine{2)- 
dioi (1,4) " and of dimethyUdiethyl-butine'diol,^^ while dimethyl- 
diphenyl-butine'diol gives, in succession, the ethylene glycol and the 
saturated glycol.*^ On the contrary, 2-^methyIrAr^henyl''bvtine{S)- 
ol{2), (CH,),C(OH) . C C . CeH^, adds 2H, immediately to ^ve the 
saturated alcohol.'* 

CHt . CHav yCH.1 • CHt 

Dimethylroctine-diol, a!(OH) .C i C .C(OH)( , 

CH,/ \CH, 

hydrogenated in alcohol solution, adds H, to form dimethyUoctene" 
diol*^ 

In the hydrogenations of these acetylene glycols, the speed of the 
reaction is usually proportional to the amoimt of catalyst present, 

» Paal, BertchU, 45, 2221 (1912). 

^* Paal and Hohbnsoobb, BerichU, 48, 275 (1915). -^ Paal and Schwabz, 
BerichU, 48, 1202 (1916). 

>T Kblbbb and Schwabs, BerichU, 45, 1951 (1912). 

u Paal and Schwabs, BerichU, 51, 640 (1918). 

^* Zalkind, /. Rti9nan Phy9. Chem. Soe,, 45, 1875 (1914), C. A., 8» 1419. 

** Zalkind and Miss Mabkabtan, J. Ruanan Phy9. Chem. Soe., 48, 538 
(1916), C. A., zz, 584. 

n Zalkind and KvAPiSHKVBKn, J. Rtusian Phys. Chem. Soe., 47, 688 (1915), 
C. A., 9, 2511. 

<* Zalkind, J. Russian Phys. Chem. Soe., 47, 2045 (1915), C. A., zo, 1355. 

^ Zalkind and Miss Mabkabtan, J. Russian Phys. Chem, Soe., 481 538 (1916), 

O. A., ZZy 0o4. 



M9 CATALYSIS IN ORGANIC CHEMISTRY 194 

but sometimes it is independent of the amoimt of catalyst, contrary 
to all predictions. 

549. The transformation of aldehydes and ketones into alcohols 
can be effected, but with difficulty. 

Bemaldehyde is partially reduced to benzyl alcohol.^* 

PhenyUacetaldehyde is regularly hydrogenated to the correspond- 
ing alcohol. 

With hydrogen at one atmosphere pressure, phorone is hydro- 
genated to dirdsobutyl-carbinol, but imder half an atmosphere, the 
reduction stops at valerone.*^ 

In acetic acid solution, mesityl oxide is hydrogenated to methyl- 
isobutyl-carbinol, but in alcohol, as stated above, the reaction stops 
at the ketone.*' The saturated alcohol is also obtained by working 
tmder 5 atmospheres pressure.'* 

550. Hydroxy-methylene derivatives containing the group 

^C : CHOH, are changed into methyl derivatives ^CH . CHg. •• 

551. Benzoic acid furnishes hexahydrohenzoicV 

552. Carvone is transformed into tetrahydrocarvone. There is 
addition of hydrogen to the double bonds of pinene, which, imder 2 
atmospheres pressure, gives pinane, of camphene which passes to 
camphane, melting at 53^,^' of eucarvone, of a- and P-terpineoU, of 
thujonsj of isothujone, of methylheptenone, of cyclohexenone, etc." 
Likewise pvlegone is changed to menthone, 

553. Naphthalene is reduced to decahydronaphthalene?^ 

554. Azohememe, in alcohol solution under 2 atmospheres pres- 
sure of hydrogen, is reduced to hydrazobenzene in five minutes and 
then into anUine in 4.5 hours. Orange No. 3 is immediately de- 
colorized imder these conditions.'** 

The a- and fi-ionones are transformed into the odorless dihydro- 
and then into the tetrahydroionones.'* 

555. Quinidine gives dihydroquinidine, melting at 165^. Cin^ 
chonidine adds H^ to form the dihydro- melting at 229®." On' 
chonine adds H, to form cinchotine}^ 

M Sktta and RrrrsB, BeriehU 43, 3393 (1910). 

» Skita, BeridUe, 48, 1486 (1915). 

>• K&sz and Schabffbr, J. prakt, Chem. (2), 88, 604 (1913). 

*7 Skita and Mbtbb, BerichU, 45t 3587 (1912). 

* Skfta and Mbtbb, BerichU, 4$, 3579 (1912). 

>• Wallach, Annakn, 336, 37 (1904). 

M Skita, Benchte, 45, 3312 (1912). 

>^ Skfta, Mbtbr and Bebgsn, Beridhl^ 45, 3312 (1912). 

•> Sktta and Nobd, BerichU, 45f 3316 (1912). 

** Paal, Qtrman paterU, 223,413. 



195 DIRECT HYDR0GENATI0N8 OF LIQUIDS 659 

Pyridine is changed to piperidine and quinoline to decdhydro' 
qidnoline." Diacetyl-morphine furnishes the dihydro- and piperme, 
tetrahydropipervne*^ 

Strychnine, dissolved in dilute nitric acid under 2 atmospheres 
pressure of hydrogen, gives the dihydro-, but under 3 atmospheres, 
tetrahydrostrychnine, while brucme always gives its dihydro-.** 

Colchicine furnishes tetrdhydrocolchicine^^ 

Egg lecithine, dissolved in absolute alcohol, gives hydrolecithine,*^ 

Use of Colloidal Platinum 

556. Colloidal platinum, prepared according to one of the methods 
given in Chapter II (67 to 71), can be substituted for colloidal palla- 
dium and gives results but little different. 

According to Paal and Gerum its activity is less.*^ According to 
Fokin, on the contrary, the platinum is three times as active and much 
more apt to hydrogenate the aromatic nucleus.** The velocity of 
the hydrogenation increases rapidly with the amount of the metal 
employed.** 

557. The reduction of ni^ro-derivatives into aminos is readily carried 
out with nitrobenzene which gives aniline and with nitrodcetophenone 
which yields aminoacetophenone.*^ 

558. The addition of hydrogen to double and triple bonds takes 
place easily even with many complex rings. 

Ethylene is transformed to ethane but less rapidly than by colloidal 
palladium, the action being proportional to the amount of platinimi 
used.*^ 

Amylene is changed to pentane, ole^ and linole^ adds into stearic 
and crotonic, mal^f aconiMc, sorbic, citraconic, and itaconic adds are 
changed into the corresponding saturated acids, while allyl alcohol gives 
propyl alcohol.*^ 

Acetylene is reduced to a mixture of ethylene and ethane.^ 

559. Heptaldeihydef hydrogenated by the aid of colloidal platinum 
prepared by the germ method, is changed to heptyl alcohol.^ 

M Sktfa and Paal, German paterU, 230,724, C, 1911 (1), 522. 

» HomcANN — La Rochb & Co., Oerman patent, 279,999, C, 1914 (2),1214. 

M Paal and Obhmb, Berichle, 46, 1297 (1913). 

*' Paal and Gsbum, Berickte, 40, 2209 (1907) and 4h 2273 (1908). 

*> FouN, /. Russian Phys, Chem. Soc., 40, 276 (1908). 

** FouN, Z. Angew, Chem., aa, 1492 (1909). 

^ Sktfa and Mbtbb, BerichU, 459 3579 (1912). 

*^ Paal and Schwabs, BeridUe, 48, 994 (1915). 

« Paal and Schwabz, BerUkU, 48, 1202 (1915). 

« Sktfa and Mbtbb, BmdUe, 45t.3589 (1912). 



660 CATALYSIS IN ORGANIC CHEMISTRY 196 

a-Methyl-fi-ethyl-propeTialf treated in acetic acid solution, is changed 
completely into a-methyl-perUanol. 

Mesiiyl oxides in water solution, goes to meihyl^cbutylrketone, but 
in acetic acid solution, into methyJrisobuiyl-^arbinoL** 

560. The aromatic nucleus is hydrogenated more or less readUy. 
With the metal prepared by the germ method, benzene is transformed 
into cydohexane. 

Toluene, in acetic acid solution under 2 atmospheres pressure, is 
changed to methyl-^ydohexane and benzoic add into hexahydrobemoic.^^ 

Cinnamic aldehyde is transformed into phenylpropionic aldehyde in 
the cold. In acetic acid solution phenylpropyl alcohol is obtained mixed 
with a little propylrbenzene, while with a larger amount of the cataljrst 
and a pressure of 3 atmospheres, cydohexyUpropyl alcohol is obtained. 
Under the same conditions, in acetic acid solution, benzylraniline fur- 
nishes hexahydrobemyUaniline accompanied by cydohexyUamine and 
methyUcydohexane,*^ 

Phenylacetaldehyde gives the corresponding alcohol with a little 
ethyl-benzene, cyclohexanol, cyclohexanone, and cydohexane. 

Benzaldehyde gives toluene and melhylrcyd^ohexane along with bemyl 
alcohol. 

Bemophenone yields dicydohexyl-^methane at 60^. 

a and p'lononee, in acetic acid solution, furnish trimethyUhy' 
droxybutylcydohexane. *' 

Caryophylleney CuHmi adds Hs in methyl alcohol solution.^' 

561. With colloidal platinum, prepared with gum arable, we can 
obtain piperidine from pyridine,*^ 

The addition of SHs takes place with various homologs of pyridine, 
hydrogenated in acetic acid solution under atmospheric pressure or 
under 2 or 3 atmospheres.^* 

The pyridine-carbonic acids are transformed into piperidinic acids.*® 
Quinoline gives, in turn, telrahydro' and then decahydroquinoline,*^ 
Diacetyl-morphine adds Hs and cinchonine yields hexahydrodncho' 
nine^^ 

«« Skita, Berichle, 48, 1486 (1915). 

« Skita and Metbr, Berichte, 45, 3689 (1912). 

M Sktta, BerichU, 48, 1685 (1915). 

«7 Skita, BeridUe, 48, 1486 (1915). 

* Dbussbn, Annalerif 388, 136 (1912). 

«* Skita and Bbunneb, Berichte, 49, 1597 (1916). 

M Hb88 and Libbbrandt, BeriehU, 50, 385 (1917). 

^ Sktta and Bbunnbb, BerithU, 49, 1597 (1916). 



197 DIRECT HYDROGENATIONS OF LIQUIDS 563 

n. METHOD OF WILLSTXTTER 

562. The process consists in submitting to a current or to an un- 
limited amount of an atmosphere of hydrogen gas, the substance 
dissolved in a suitable vehicle and intimately mixed by means of con- 
stant agitation with the plcUinum or palladium black. It was employed 
first by Fokin, who transformed in this way oJatc add dissolved in ether 
into stearic acid by a current of hydrogen in the cold with palladiimi 
or platinmn black as cataljrst."* 

But Willst&tter is the one who has generalized this method by 
applying it to various uses. 

Platinum black prepared according to the method of Loew (62) 
serves best." Palladium black can also be used: it is prepared by 
reducing palladoua chloride with formaldehyde in the presence of caus- 
tic soda.*^ But it is not so desirable as platinum black. 

The substance dissolved in ether or in any other inert solvent is 
treated with the platinum black and is put into a flask which is continu- 
ally agitated by a mechanical shaking machine and which conmiunicates 
with a gasometer filled with hydrogen. According to circumstances, 
quite different amounts of platiniun black are used, varying from 3 
to 33% of the weight of the substance. 

Dilution of the material is not indispensable to the success of the 
method. 

Use of Platinism Black 

563. Willstatter has called attention to this quite unexpected fact, 
that in certain cases hydrogenation by means of platinum black is 
not possible unless it has been previously charged with a certain pro- 
portion of oxygen. 

In most cases, platinum black containing oxygen or free from oxy 
gen may be used indifferently, as in the hydrogenation of benzene to 
cyclohexane; on the contrary, the hydrogenation of pyrrol requires 
platinum black absolutely free from oxygen. On the other hand, the 
decomposition of hydrazine demands that the platinum black that is 
to be used be previously aerated.** 

The aeration of the platiniun black is indispensable for the hydro- 
genation in acetic acid solution of phthalic and naphthalic anhydrides 
and the reaction does not continue unless the apparatus is opened 

** FouN, /. RuBsian Phys. Chem. Soc,, 39, 607 (1907). 
** Somewhat improved method WnxBTlTTSB and WALDSCBiaDisLBm, BeriefUe. 
54, 121 (1021). — E. E. R. 

*^ Bbbtbau, Div. mith. d^hydr. app, au Ph^natU, Paris, 1011, p. 25. 
** PuBGom and Zanicbblu, Oat. Chim. lUd., 34 (1), 57 (1904). 



664 CATALYSIS IN ORGANIC CHEMISTRY 198 

from time to time for the aeration of the black. Oxygen appears to 
play an active part in the hydrogenation which is indicated by the 
products obtained. For phthalic anhydride the products are, hexahy* 

yCH,v 

drophihalid, CeHuw yO^ chexahydrotoluic and hexahydraphthaUc 

adds, and for naphthalic acid, tetrahydronaphihalidy hexahydronaph" 
thalidy decdhydroacenaphihene, CuHioy and tetrahydr(Hnethyl(l) naphUuir 
lene-carhonic acid{8). 

The influence of these anhydrides on the conditions of hydrogenation 
can effect even the hydrogenation of the dibasic acids themselves; 
the presence of the anhydrides prevents this from taking place imless 
the platinum be aerated. laaphthalic acid, which usually contains traces 
of the anhydride, can not be hydrogenated except with aerated 
platinum.*' " 

564. Nitro Compounds. The reduction of nitro or nitroso com- 
pounds to amino is readily effected by 1 eg. of platinum black to 1 g. 
of the material dissolved in ether or acetone. A few minutes are suf- 
ficient for complete reduction; thus p.nUrotoluene is changed to 
p.toluidine, l^nitrosonaphtholit)^ into aminanaphthol. But the nitroso- 
terpenes are changed quantitatively into the corresponding hydrox- 
ylamines.*' 

565. Ethylene Double Bonds. These are readily saturated. 
Amylene is changed to penfane. 

(o-Nitrostyrene, dissolved in absolute alcohol or in glacial acetic 
acid, adds a single atom of hydrogen, two molecules combining**: 

C«H».CH : CH.NO, C«H6.CH.CH,.N0, 

CaHfi . CH : CH . NO, ' C^, .'CH . CH, . NO, 

Oyic alcohol is readily transformed into odadeeyl alcohol, ethyl 
oleate quantitatively into ethyl stearatBy and erudc alcohol into docosyl 
alcohol. 

*« Wnj^TATTBB and Jacqubt, Beriehte, 51, 767 (1918). 

*' In a more recent article WoiLBtJLttbb and WALDSCHMnyr-Lflrrz [Berickte, 
54i 113 (1920) ] show that the presence of oxygen in the platinum black is neces- 
sary in all cases. This oxygen is graduaily used up by the hydrogen during the 
process of hydrogenation. With ethylene compounds the addition of the hydrogen 
is BO extremely rapid that the desired hydrogenation may be accomplished before 
the catalyst becomes inactive by loss of its oxygen but if the hydrogenation is 
slow, the catalyst may require revivification by aeration at intervals during the 
process. In this respect palladium black and even nickel act similarly to platinum 
black. — E. E. R. 

»• CxjSMANO, Lincei, 26 (2), 87 (1917). 

** SoNN and ScmnniLBMBBBQ, Beriehte, 5O9 1913 (1917). 



199 DIRECT HYDROGENATIONS OF LIQUIDS 667 

Phytene, CioH^o, gives phytane, CsoHis; phytol, CioH»OH, dihydro- 
phytol, GsoHiiOH, slowly but with a good yield. Geraniol (416) is 
hydrogenated only slowly and gives the corresponding saturated alco- 
hol at the end of several days.*** 

Linalool furnishes g, d-dimelhyJrOctanoliS).^^ 

Safrol and iaoaafrol are hydrogenated in two hours to dihydrosafroL 
Likewise eugenol and isaeugenol pass into iaapropyUguaicLCol.^ 

Piperonalrdcetone and dipiperonal-acetone are transformed into the 
saturated ketones.** 

Chdesterine, in ether solution with one third its weight of platinum 
black, is changed into dihydrocholesterine in two days.*^ 

Oyic add gives stearic and ethyl oleaie yields ethyl aiearate.*^ 

566. Acetylene Triple Bonds. The acetylene glycols of the formula, 
RR':C(OH).C:C.C(OH):RR', give the corresponding saturated 
glycols and also certain amounts of the alcohols, RR' :C(OH)CHs.- 
CHj.CH, : RR'.** Thus «, &4imeOiyUhexine{S)diol{g, 4) furnishes the 
saturated glycol.** 

IHiMthyMieihyJrbiUin&-diol, which adds only Hs with colloidal pal- 
ladium (548), takes up 2Hs with platinum black.*' 

IXmethyMiphenyl-biUine^iol can add Hs 6jxd then 2Hs by steps.** 

Octadi4ne^iol{l,8), HOH,C.C • C.CH,.CH,.C i C.CH,OH, hy- 
drogenated at 70° in alcohol^ solution, gives a mixture of octane^iol 
{1, 8) and n.odyl alcohol^* 

0ctadi4ne^ioic add, HO,C.C • C.CH,.CH,.C • C.COiH, dissolved 
in a mixture of alcohol and ether, fiutiishes suberic add in four 
days.^* 

567. Aldehydes and Ketones. Aldehyde and ket<me groups can be 
regularly transformed into the corresponding alcohol groups. CroUmic 
aldehyde, in anhydrous ether, is changed in eleven hours into a mixture 
of 70 % biUyric aldehyde and 30 % butyl alcohol.''^ 

** Wni^TlTTBB and Matsb, BerichtSf 41, 1475 (1908). 

^ Babbbbb and Locquin, Campt. rend., z58» 1555 (1914). 

« FouBNiBB, BiiU. 80c, Ckim. (4), 7, 23 (1910). 

^ Vavon and FAiLLBsm, Compt. reruL, 16^9 65 (1919). 

*« WnjOTlTTEB and Matsb, Beriehie, 41, 2199 (1908). 

* DiTPONT, CompL rend., 156, 1623 (1913). 

** Zalkind, J, Russian Phye. Chem, 80c., 45, 1875 (1914), C. A., 8» 1419. 

^ Zaxjond and Miss Mabxabtan, /. Russian Phys, Chem, Soc,, 4S1 538 (1916), 
C. A,, 11, 584. 

** Zauomd and EvAPiSHBVBxn, /. Russian Phys. Chem. Soc., 47, 688 (1915), 
C. A., 9, 2511. 

n LsspiBAn, Compt. rend., 158, 1187 (1914). 

'Q Lbbpudau and Vavon, Compt. rend., 148, 1335 (1909). 

^ FouBNiBB, BvU. See. Ckim. (4), 7, 23 (1910). 



668 CATALYSIS IN ORGANIC CHEMISTRY 200 

Acetone is changed to iaaprapyl alcoliol in water solution and methyU 
ethylrketone is changed into methyUethylrcarhinoL in 12 hours. Diethyl 
and dipropyJrkeUmea are similarly reduced. 

The transformation into the alcohol is more readily effected with 
cydoperUanone dissolved in 5 volumes of ether, with qfdohexanone and 
with the methylrcydohexanones. 

Mesityl oxide gives first methyldedbutyUkeUme and then methyU 
iaobtUyJrcarbinol. 

In ether solution, phorone yields diieobtUyl-ketone, while in acetic 
acid it gives diisobtUyl-carbinol. 

Citral in ether solution gives a mixture of g, d-dimethylrodane and 
g, e-dimethyl-octanol (8).'^ 

MenOione yields merUhol and pulegone gives pulegomenOiolJ* Carvone 
with 20 % of platinum black takes up in succession, Hs, 2Hs, 3Hs to 
form carvotanaceUme, tetrahydrocarvone and finally carvomenthol slowly .^^ 

568. Aromatic aldehydes are transformed almost quantitatively 
into alcohols, which is a valuable reaction since other methods give 
hydrocarbons (388). With 10 g. of black a gram molecule can be hydro- 
genated in a few hours. This can be done with benzaldehyde, methyl- 
salicylic, benzoyUsalicyliCy and anisic aldehydes, vaniUine and its methyl, 
ethyl, acetyl, and benzoyl derivatives, piperonal, which gives the alcohol 
melting at 54^, and cinnamic aldehyde, which yields phenyUpropyl 
alcohoU^ 

At 70^ anisaldehyde gives anisalcohol but at 97° it is polymerized. 
On the contrary, acetophenone takes up 10 atoms of hydrogen at 
once to form ethyt-cydohexaneJ^ 

569. Aromatic Nucleus. Aromatic compounds are completely 
hydrogenated to cyclohexane derivatives on the condition that they are 
perfectly pure. Traces of impurities, particularly sulphur compounds, 
hinder the reaction.'^ 

Toluene and the xylenes are hydrogenated more readily than ben- 
zene, and higher homologs still more readily. Butyl4>enzene, amyU 
benzene, hexyl-henzene, ociyl-henzene, etc., up to pentadecyl-benzene are 
readily changed in acetic acid solution into the corresponding cyclo- 
hexane derivatives.^* 

Durene furnishes hexahydrodurene. 

" Vavon, Ann. Chirn. (9), x, 144 (1914). 

« Vavon, Compi. rend., 155, 287 (1912). 

7« Vavon, Compt. rend,, 153, 68 (1911). 

^ Vavon, Compi. rend., 154, 369 (1912). 

w Vavon, CampL rend., 155, 287 (1912). 

^ Wm^JLTTEB and Hatt, Beriehte, 45, 1471 (1912). 

'• HAiisa, /. praki. Chem. (2), 9a, 40 (1915). 



201 DIRECT HYDROGENATIONS OF LIQUIDS 670 

Styrene gives ethyUcydohexane;''* and phenol^ cyclohexanol,'" 

Eugenol adds 4Hs to form propyl-^methozyHyyclohexanoL*^ 

Aniline produces chiefly diq^dohexylramine with only 10 % of q/cZo- 

hexylramine. Chlortoluene is transformed into meihylrchlorcyclohexaneJ' 
In ether solution, benzoic add is slowly changed to hexahydrobemoic 

add without intermediate products. ^^ 

In acetic acid solution, p.amincbenzoic add is quantitatively reduced 

to pMndnocydohexane-carbonic acid and hydroxybenzoic acid is similarly 

hydrogenated." 

We have seen above (563) that phthalic anhydride can be hydro- 

genated by means of platinum black aerated from time to time. The 

ordinary method serves well for pJUhalimide which gives as the sole 

product, hexahydraphthalimide:^ 

;nh. 

CHj.CHj.CH^.CO/ 

570. Terpenes. Limanene, in ether solution with 25 % of its weight 
of platinum, adds Hs in 30 minutes in the cold to form carvomenihenef 
boiUng at 175°, and then an additional Hs in 65 minutes to form 
menihane,** 

Pinene, 500 g. with 15 g. platiniun, absorbs hydrogen rapidly, 60 L 
per hour at the start, and at the end of 24 hours is entirely transformed 
into dihydropinene, boiling at 166° (477). Camphene gives a solid 
dihydrocamphene melting at 87°.** 

a-Thujene, CieHu, which by the method of Sabatier and Senderens 
yields menthane (478), is totally transformed by platinum black and 
hydrogen under 25 to 50 atmospheres in two days into thujane, CioHis, 
boiling at 157°, the inner ring remaining intact. Similar transforma- 
tions take place with ff-thujene and with sabinene.*^ 

Isoamylrcarvol adds 2H2 to give the corresponding saturated 
alcohol.*^ 

The sesquiterpenes, CibHs4, as well as their ketone and alcohol 
derivatives, add 4 or 6 atoms of hydrogen. 

'• WoiLBTXrrBB and Exng, Beriehte, 46, 527 (1913). 

** Madinavxitia and Blanks, 8oe. Etpan. Fia. Qvim,, zo, 381 (1913), C, A., 
7, 3600. 

n WniLBTlTFEB and Matsb, BerichU, 41, 1475 (1908). 

M HoxTBBN and Pbau, BeriehU, 49, 2294 (1916). 

•• WttLfirrATTBB AND Jacqttst, BeHchUj 51, 767 (1918). 

M Vavon, Bva. 80c. Ckim. (4), 15, 282 (1914). 

• Vavon, Cwnpt. rend., 149, 997 (1909) and 152, 1675 (1911). 

** TcHOUGASFF and Fomin, Campt, rend., 151, 1058 (1910). 

*7 SiBiafUDB, Jonas and Oxlsneb, BeridUe, 50, 1838 (1917). 



671 • CATALYSIS IN ORGANIC CHEMISTRY 202 

Thus iaozingiberenef^^ eudeamene,^* and fendene,^ take up 2Hj. The 
same is true of doremone, CuHasO, which gives tetrahydrodoremone with- 
out alteration of the ketone group and of doremol which forms the sat- 
urated alcohol. Famesol, CuHmO adds 3Hs.*® 

Betvlol, CuHmO, adds 2Hs to form the alcohol, CuHagO, when it 
is hydrogenated in anhydrous ether solution.^^ 

571. Complex Rings. CycUhoctenone is changed to qfcUhodanone 
hy 10% of its weight of black. Cydo-octcUriene and cydo-octoMrene^ 

CH:CH.CH:CH 

* I are transformed into cycUhodane,^ 
CH:CH.CH:CH 

In the hydrogenation of the latter, the first three Hs are fixed with 
about the same velocity, while the last Hs is added only about half so 
fast" 

Naphthalene adds hydrogen rapidly to form the dihydro- and then 
the tetrahydro* and finally, more slowly, decahydro-wiphlhalene,^ 

Phenanthrene, dissolved in ether, ^ves dihydra^henarUhrene (melt- 
ing at 94^), in two days in the cold, or in 8 hours at the boiling point 
of the ether.** However, Breteau failed to obtain any hydrogenation 
in cyclohexane solution. •• 

Santonine yields tetrahydro-santanine when hydrogenated in glacial 
acetic acid.^ Sodimn santonate takes up the same amount of hydrogen 
to form sodium tetrahydrosantonate."^ 

Pyrrol adds 2H2 to form pyrrolidine.^* 

Indol, in glacial acetic acid, yields odahydro^ndolf an alkaline 
liquid with a disagreeable odor boiling at 182°, accompanied by a Uttle 
dihydro^ndol, ^^ 

572. Quinine sulphate is completely hydrogenated in dilute sul- 
phuric acid solution by hydrogen under a pressure of more than an 
atmosphere to dihydroquinine sulphate, the hydrogenation being con- 

m _ 

M Semmlbb and Bbckbb, BeridUe, 46, 1814 (1913). 
•• Sbmmlbb and Rissb, BeridUe, 46, 2303 (1913). 
^ Sbmmlbb, Jonas and Robnisgh, Berichie, 50, 1823 (1917). 
n Sbmmlbb, Jonas and Rich^tbb, BeridUe, 51, 417 (1918). 
• WnxsTJLiTBB and Wasbb, BeridUe, 44, 3434 (1911). 
** Wn^LST&TTEB and HBrnBLBBBOEB, BeridUe, 46, 517 (1913). 
•* WiLiBTiTTBB and Hatt, BeridUe, 45, 1471 (1912). — WiLiJ3TiTTBB and 
King, Ibid., 46, 527 (1913). 

" ScHMmr and Fischbb, BeridUe, 41, 4225 (1908). 

H Bbbtbau, Mith, d^hydrog. app. au PhinarU, Paris, 1911, p. 20. 

^ AsAHiNA, BeriehU, 46, 1775 (1913). 

M CuBMANO, Lincei, aa, 507 (1913). 

•• WillstJLttbb and Hatt, BeriehU, 45, 1371 (1912). 

iM WnjiflTlTTBB and Jacqxtbt, BeridUe, 51, 767 (1918). 



203 DIRECT HYDROGENATIONS OF LIQUIDS 676 

tinued till the solution does not decolorize potassiiun permanganate.^®^ 
Dihydromorphine and dihydrocodelne can be obtained in the same 
way.^" 

Use of Palladium Black 

573. The use of palladium black ^°* immersed in the liquid appears 
to be usually less advantageous than the use of platinum black. How- 
ever^ it has led to some remarkable results, such as the reduction of 
carbonates to formates. 

574. Reduction without Addition of Hydrogen. The most important 
reaction is the synthesis of formates by the reduction of bicarbanates: 

KHCOs + Hj - HCOjK + H^O. 

This requires a high pressure and a temperature around 70^. 

In a silver plated bomb, 10 g. potassiiun bicarbonate, 200 cc. water, 
ai^d 1 . 5 g. palladium black are placed with hydrogen at 60 atmospheres. 
After heating for 24 hours to 70^ 74.7% of the salt is changed to 
formate. 

The reaction takes place without catal3rst, but extremely slowly, 
only 0.6 % of formate being produced in 24 hours. 

The potassium bicarbonate can be replaced by sodium borate, the 
bomb then being filled with equal volumes of carbon dioxide and hy- 
drogen under 60 atmospheres.^*^* 

The reaction can be carried out without the presence of the alkali 
salt, by maintaining a mixture of carbon dioxide and hydrogen under 
high pressure in the presence of water and palladiiun black. By working 
at 20^ and under a pressure of 110 atmospheres a 1 % solution of formic 
add is obtained.^" 

575. Reduction of Acid Chlorides. Another reaction which is 
peculiar to palladium black is the reduction of add chlorides to aldehydes : 

R.COCl + H, - R.CHO + HCl. 

The acid chloride, dissolved in a hydrocarbon, is submitted to hy-< 
drogenation in the presence of palladiiun black precipitated on barium 
3ulphate. 

Benzoyl chloride gives benzaldehyde with a yield of 97 % ; butyryl 

in YBBsm, GmNiNTABB. ZoocsB & Co., Engliak paimU 3,948 of 1912. 

i> Oerman patent 200,233. 

^* Preparation — WnxsrlTTEB and WALDScmaDT-LBiTZ, Berichte, 54, 123 
(1921). — RE. R. 

^^ Bbedio and Cabtxb, Beriehte, 47, 541 (1914). 

^ Bbedio and Gabtxb, English pcOent^ 9,762 of 1915; /. S. C. /., 34, 1207 
(1915). 



676 CATALYSIS IN ORGANIC CHEMISTRY 204 

chloride furnishes 50 % of the aldehyde and sUaryl chloride is reduced 
to its aldehyde.^^^ 

576. Nitro Compounds. The reduction of nitro to amino com- 
pounds is difGicult to carry out with palladium, but nitrobenzene does 
give aniline on prolonged contact with an excess of hydrogen and 
palladium black in alcohol solution. ^^ 

577. Ethylene and Acetylene Bonds. Oleic add, in ether solution, is 
slowly transformed to stearic acid, the reduction being rapid when it 
is carried on at a higher temperature and with hydrogen under pres- 
sure. The same is true for the esters of oleic acid and this is the basis 
for the industrial use of palladium black in the hardening of liquid 
fats (946). 

yCHj 
Vinyl-trimethylene, CHj:CH.CH^ I , treated in the cold with 

hydrogen under 35 atmospheres in the presence of palladium chloride, 
which is reduced, yields ethyl-trimethylene."' 

The acetylene glycols of the type, RR' :C(OH).C • C.C(OH) 
: RR', yield mainly the saturated hydrocarbons, RR' : OH . CHs . CHt- 
CH :RR'."* 

Eugenol stops with the formation of dihydroeugenolf^^^ the ring not 
being hydrogenated as with platinum black (569). 

578. Aromatic Nucleus. The hydrogenation of the aromatic nu- 
cleus is not usually effected by palladiimi black, but the hydrogenation 
of hexahydroxybenzene to inosite at 50-55^ may be mentioned. The 
inosite formed melts at 218^ as does natural inosite.^^^ 

579. Phenanthrene is hydrogenated, in cyclohexane solution, by 
half its weight of the black to tetrahydrophenanihrene.^^ 

Use of other Metals of Platinum Group 

580. Ruthenium Black. The black prepared by formaldehyde and 
rutheniiun chloride solution has a catalytic activity inferior to that of 
platinum. 

If 0.05 g. of this black is added to 0.5 g. dnnamic acid in 2 cc. 
glacial acetic acid, phenyl-propionic acid is formed in 8 hours without 

^^ RoBBNMXTND, Betichte, 51, 585 (1918). 
^^ GsBTTM, Inaug, Dissertation, Erlangen, 1908. 
iM FiLippov, /. Russian Phys. Chem. 80c., 44, 469 (1912). 
»•• DuPONT, Compt. rmd., 156, 1623 (1913). 

*^^ MADmAVXiTiA and Blanks, 80c. Espan, Fis, Quim,, zo, 381 (1913), C. A., 
7, 3500. 

^" WuBLAND and Wishobt, Berichle, 47, 2082 (1914). 
"* Bbbtbau, Div, mMh, hydrog,, Paris, 1911, p. 26. 



206 DIRECrr HYDROGENATIONS OF LIQUIDS 583 

the ring being attacked. Toluene, dissolved in acetic acid and sub- 
jected to hydrogenation for 8 hours, is not affected.^" 

581. Rhodium Black. Rhodium black is more active than ruthe- 
nium. Under the conditions given above, dnnamic add is transformed 
into phenyJrprojnonic in 3 hours and into cydohexyl-qtropionic in 15 
hours. Toluene can be hydrogenated to hezahydroioluene in 12 hours 
by 10% of its weight of the black."* 

582. Iridium Black. This black prepared by reducing the chloride 
by sodium formate, has an activity entirely analogous to that of ruthe- 
nium black (580).i» 

583. Osmium Black. This black, prepared by reducing osmic 
anhydride by formic acid, does not effect any hydrogenation of dnr 
namic add in 5 hours. ^" 

Osmium dioxide has been mentioned as able to hydrogenate oils 
when used to the amount of 0.5 %,"^ but it is certain that it acts after 
it is reduced to the metal which is the true catalyst.^" 

"* Madinavxitia, Soc Etpan, Fis. Quim., zx, 328 (1913). 

u« Lbhmann, Arch. Pham., 251, 152 (1913), C. A., 8, 586 (1914). 

^ NoBMAN and Schick, Arch. Pharm., 253, 206 (1914). 



CHAPTER XII 

HYDR06ENATI0NS (Continued) 

DIRECT HYDROGENATION OF LIQUIDS IN CONTACT 
WITH METAL CATALYSTS {Continued) 

III. METHOD OF IPATIEF 

584. This method consists in wanning the substance to be hy- 
drogenated in contact with nichel or nickel oxide and hydrogen com- 
pressed to at least 100 atmospheres in a very strong container. The 
hydrogenation velocity is greater when the oxide is used, which Ipatief 
attributes to the real catal3rtic power of the oxide. As we have seen 
above (80), catalytic power appears to belong exclusively to the metal; 
since the temperature is always above 250^, the nickel oxide must at 
least in part be reduced to the metal which is more active than the 
metal prepared in advance and which has been subjected to incandes- 
cence more or less intense while being introduced into the container, 
being thereby agglomerated and reduced in catal3rtic power. 

The nickel is frequently replaced by copper, copper oxide, iron or 
palladium, or even by zinc powder. 

585. Apparatus. The apparatus used for all of this work consists 
of a soft steel tube lined with copper, holding 250 to 275 cc. and capa- 
ble of sustaining 600 atmospheres at 600^.^ It is heated electrically by 
a nickel resistance wire. Changes of pressure are shown by a manom- 
eter. If the apparatus has been filled with hydrogen at a certain 
pressure, the pressure increases according to the rise of temperature, 
if there is no absorption of hydrogen or evolution of gas, but less 
rapidly if there is absorption of hydrogen, while if there is decompo- 
sition with evolution of gas, the pressure increases more rapidly and 
this increase measures the rate of decomposition. 

The material of which the apparatus is constructed appears to 
influence the results in some way. Thus in a bronze tube the use of 
reduced copper as catalyst did not efltect the complete hydrogenation 
of the aromatic nucleus, while this was realized in an iron apparatus.* 

1 IPATisr, Berichie, 37, 2961 (1904).--/. Russian Phys. Chem, 80c., 36, 786 
(1904), C, 1904 (2), 1020. 

* Ipatixf, /. Ritssian Phys. Chem. 80c., 4a, 1557 (1910). 

206 



207 LIQUIDS IN CONTACT WITH METAL CATALYSTS 687 

Use of Nickel 

In order to carry out a hydrogenation, about 25 g. of the material 
to be hydrogenated is placed in the apparatus with 2 to 3 g. nickel 
oxide (NiO or Ni20t) and hydrogen is admitted to 100 atmospheres at 
which pressure it holds about one gram molecule of hydrogen. The 
temperature of heating may reach 400^ or even 600° and the resulting 
pressure may be 2.5 or 3 times the original, i.e. 250 to 300 atmos- 
pheres. The necessity of having an expensive apparatus and the real 
dangers of its use are against the general employment of the method 
of Ipatief , which is not superior to the method of Sabatier and Sender- 
ens except in special cases where the slowness of hydrogenation or the 
need of high pressures requires its use. Most organic substances give 
the same products by both methods. 

586. Formation of Methane. The direct hydrogenation of carbon 
in the presence of nickel, oxide of nickel, or nickel oxide and alumina, 
does not take place below 600° under moderate pressures of hydrogen, 
but under very high pressures, methane is produced above 500°, the 
amount increasing with rise of temperatiu^. 

The reduction of carbon dioxide to methane which takes place in- 
completely at 450° under ordinary pressure, is not more complete at 
high pressures even with an excess of hydrogen.' 

587. Ethylene Double Bonds. The hydrogenation of substances 
containing ethylene bonds is readily effected. 

Oleic add heated a long time at 100° with finely divided nickel 
and hydrogen at 25 atmospheres is not affected, but under 60 atmos- 
pheres pressure it is changed to stearic add in 12 hours. Liquid fats 
are transformed to Bolid^ 

50 g. cottonseed oU with 3 g. nickel oxide at 220-230° with hydrogen 
at 60 atmospheres gave in 4 hours a fat with iodine number (938) of 
only 11, while at ordinary pressures this result was obtained only at 
255.°» • 

DimethyJrdllylrcarbinol is changed to dim^thyl-propyJrCarbinol under 
the same conditions. 

At 140 to 150°, msdtyl oxide gives methyldsobutyJrketone mixed with 
a little of the corresponding alcohol. 

Cydohexene is reduced to cydohexane. 

• Ifatibf, /. prakt. Chem. (2), 87, 479 (1913). 

< Foxm, /. Ru99ian Phys. Chem. Soc,, 38, 419 and 855 (1906>. 

• Ifatibf, J. Rturian Phya. Chem. Soc., 46, 302 (1914). 

• With hi^ speed stirring this reduction can be accomplished in about the 
same time with 0.1 g. nickel on infusorial earth with hydrogen at atmospheric pres- 
sure at 180^. — E. £. R. 



688 CATALYSIS IN ORGANIC CHEMISTRY 208 

588. Aldehydes and Ketones. The transformation of aliphatic 
aldehydes and ketones into the alcohols can be accomplished, but it is 
limited by the inverse reaction of dehydrogenation especially when the 
temperature exceeds 200 to 250^. 

Isobutyrie and isovaleric aldehydes are partly reduced to the corre- 
sponding alcohols at 250^ and 100 atmospheres. 

At 250^ acetone is completely changed to isopropyl alcohol and the 
same is true of various aliphatic ketones at around 200^. At about 
280° the hydrogenation is limited by the inverse reaction which in- 
creases with elevation of temperature. From 300 to 325° acetone no 
longer gives any alcohol since isopropyl alcohol is decomposed into 
water, propane and lower saturated hydrocarbons, especially methane.^ 

Laevulose in solution is transformed, at 130° under 100 atmos- 
pheres, to a-^mannite, ghicose into sorbite^ and galactose into dvlcUs, 

589. Aromatic Nucleus. The hydrogenation of the aromatic nu- 
cleus is reaUzed in all cases. 

Benzene is totally changed to cydohexane in 1.5 hours at 250° with 
8% nickel oxide. Nickel sesquioxide gives better results than the 
monoxide. At 300° the cydohexane produced does not remain but is 
decomposed into benzene, methane and carbon.' 

At 250° diphenyl is reduced to dicydohezyl and dibenzyl to dicydo- 
hezylethane. 

At 245° phenol is transformed in 14 hours to cyclohexanol accompan- 
ied by some cydohexane. At 200° hydroguinone gives quinite.* The 
product is a mixture of the cis and trans forms, but the yield is poor, 
as most of the diphenol goes into resinous products. ^^ 

At 230° under 100 atmospheres, phenyl oxide gives in 12 hours a 
mixture of cydohexyl oxide, cyclohexanol and cydohexane,^^ 

Anisol, CeHfiOCHt, in 24 hours at 240° imder 100 atmospheres, 
gives 40% hexahydroanisol accompanied by cyclohexanol and cydo- 
hexane. 

Guaiacol, o.HO.CeHi.OCHi, in 12 to 15 hours at 220 to 240° and 

100 atmospheres, yields hexahydrogtiaiacol with cyclohexanol and a 

Uttle cydohexane." 

' Ipatixf, /. RtMian Phys. Chem, Soc, 38, 75 (1906) and 39, 681 (1907), C. A., 
I, TSri. — BerichU, 40, 1270 (1907). 

• iFATmr, /. Russian Phys. Chem. Soe., 39, 681-693 (1907), C. A., z, 2877 and 
2878. 

• Ipatibf, /. Russian Phys. Chem. Soe., 38, 75 (1906) C, 1906, (2), 86.— 
BeriehU, 40, 1281 (1907). 

** Ipatibf and Louvoooi, /. Russian Phys. Chem. Soc., 46, 470 (1914). 
u Ipatibf and Pmupow, /. Russian Phys. Chem. Soc., 40, 501 (1908), C, 
Z908 (2), 1098. — Ipatibf, Berichie, 41, 993 (1908). 

" Ipatibf and LouYoaoi, /. Russian Phys. Chem. 80c., 46, 470 (1914). 



209 LIQUIDS IN CJONTACT WITH METAL CATALYSTS 690 

590. The hydrogenation of phenols having unsaturated side chains 
is accomplished in two steps. At 95^ and 30 to 50 atmospheres, only 
the side chain is attacked but by raising the temperature to 185 to 
200^, the nucleus is also hydrogenated. 

Thus, aneOiol p.CH,0.C«H4.CH iCH.CH,, with 10% nickel at 
95^ and 50 atmospheres is transformed completely in 4 hours to 
methoxy-propylrbenzeney but 20 hours at 200** produce propyl-cycUh 
hexane, the methoxy group being reduced to water and methane. 

Likewise eugenolf H8C(HO)C6Hs.CH2CH : CHj, s,nd isoetigenol, 
H^(H0)C«H8.CH rCH.CHi, furnish methaxy-propylrphenol in 2 or 
3 hours at 29**, while at 195** in 7 hours, the chief product is methoxy^ 
propyl<yclohexane, HsCOCeHio-CsHy, the phenol group being elim- 
inated. 

The methyl ether of eugenol adds only H2 at 95**, but in 10 hours at 
210**, the same product is obtained as from eugenol. 

Safrol and isosafrol are not hydrogenated at ordinary pressure at 
140 to 160** with constant agitation for 5 hours, but under 50 atmos- 
pheres at 93**, dihydrosafrol, boiling at 228**, is obtained in 2 hours. 
In 10 to 12 hours at 180**, a product is obtained boiling at 207** which 
appears to be methoxy-propyl-^clohexane.^* 

By 50 hours heating at 220** under 115 atmospheres, aniline gives 
40 to 50 % of cydohexyUaminey about 10 % dicydohezyUamine and some 
q^dohexyUaniline. " 

Diphenyl^mine yields dicydohexyUamine.^^ 

Bemaldehyde, at 200**, gives toluene and methyUcydohexane,^^ while 
at 280** in 12 hours, toluene, dibenzyl and resinous products are 
obtained." 

Aromatic ketones act as they do in Sabatier's process (389) and 
yield hydrocarbons, benzophenone going into diphenyl^methane and 
bemolne into dibenzyl^ ^^ 

Ipatief's process is useful for the hydrogenation of aromatic acids, 
but it is not well to use the free acids which attack the nickel 
nor the esters which give poor results (ethyl terephthalate is decom- 
posed into ethyl p.toluate, methane and carbon dioxide), but the 
alkaline salts. Thus potassium bemoate gives 40 % of the hexahydro^ 
bemoate at 280** in 9 hours and sodium bemoate is even more readily 
hydrogenated. 

» Ipatixf, Beriehte, 46, 3580 (1913). 
i« Ipatdbf, BeriehU, 41, 903-1001 (1008). 

u Ipatebf, /. Russian Phys. Chem. 80c. 40, 401 (1008), C, 1908 (2), 1008. 
^* Ifatdbf, /. Russian Phys. Chem. Soc., 38, 75 (1006), C, 1906 (2), 86. 
" Ipatibf, /. Russian Phys. Chem. 80c., 38, 75 (1006) and 39i ^^ (1^7), 
C. A., X, 2877. 



691 CATALYSIS IN ORGANIC CHEMISTRY 210 

Potasaium phihalaie gives the hexdhydrophthdUUe at 300^ in good 
yield." 

Sodivm cinnamate gives the cydoIiexyJrpropionate at 300^ under 100 
atmospheres." 

591. Teipenes. Terpene compounds undergo the regular trans- 
formations.*® 

lAmonene is transformed into dihydrolimonene and then into menr 
thane at 300-320^ under 120 atmospheres. 

At 265^ pinene gives pinane and merUhane at 300^. 

At 240°, in 10 to 15 hours, camphene furnishes an isocampJiane 
melting at 57"" and boiling at 162.5''. 

At 280^ under 120-130 atmospheres, carvone passes into carvomerir 
ihone. At 220°, puUgone gives menthone, which at 280° is mixed with 
menthane. 

Camphor is completely changed into bomeol at 350°. 

592. Various Rings. At 250° under 120 atmospheres, naphthalene 
gives, in turn, tetrahydro- and decahydro-naphthalene. 

The a- and ^-naphtJioh are changed to a- and fi-^ecahydronaphthols, 
melting at 57° and 99° respectively.*^ 

Anthracene^ submitted to repeated hydrogenations at 260-270° 
under 100 to 125 atmospheres for 10 to 16 hours, gives in succession, 
ietrahydro; decahydro- (m.73°) and &naMy perhydroanthracene (m.88°) 
and at the same time is partially destroyed. 

At 400°, phenanthrene gives better results, the dihydro- and then 
the tetrahydro- being obtained and, by a second operation, the oda- 
hydro- and perhydrophenanthrene with the odor of caoutchouc.** 

QuinoUne first yields tetrahydroquinoline and then, almost quantita- 
tively, decahydroquinoline.^ 

Use of Iron 

593. At 350-400°, iron transforms aliphatic aldehydes and ketones 
into the alcohols. Acetone, at 400° and 103 atmospheres in 20 hours 
yields 25 % of isopropyl alcohol. leobulyric aldehyde gives 75 % of the 
corresponding alcohol at 350°, but acetaldehyde is partly resinified and 
partly decomposed into carbon monoxide and methane. 

^ Ipatibf and Pmupow, /. Russian Phys, Chem, 8oc,, 40, 501 (19i}8), C, 1908 
(2), 1098. — Ipatibf, BerichU, 4h 993 (1908). 

^ Ipatibp, /. Russian Phys, Chem, 80c, , 41, 1414 (1909). 

*^ Ipatibp, BeriMe, 43, 3546 (1910). — Ipatibf and Matow, Berichte, 45, 3205 
(1912). 

» Ipatibf, /. Russian Phys. Chem. 80c., 39, 693 (1907), C. A., i, 2877.— 
Berichte, 40, 1281 (1907). 

<■ Ipatibf, Jakowlbw and Rakpfin, Berichte, 41, 996 (1908). 

» Ipatibf, /. Russian Phys. Chem. 80c, 40, 491 (1908), C, 1908 (2), 1098. 



211 LIQUIDS IN CONTACT WITH METAL CATALYSTS 696 

The hydrogenation of the aromatic nucleus does not take place, 
even at 420®, but cyclokexane is brought back to benzene.** At 280® 
benzaldehyde gives a mixture of toluene and dtbenzyl. The same result 
is obtained when benzyl alcohol is hydrogenated at 350® and 96 atmos- 
pheres.** 

Use of Copper 

694. Copper, or copper oxide (certainly reduced to the metal), 
readily permits the hydrogenation of ethylene bonds at 300 to 350® 
under 100 to 200 atmospheres, but when used alone does not effect 
the hydrogenation of the benzene ring.*^ 

Sodium cinnamaie is changed to the phenyUpropionaie.^ 

Unsaturated side chains of phenols are saturated at 270 to 300^ 
without modification of the nucleus.*" 

Acetone yields 65 % of isopropyl alcohol at 280-300®. 

Pinene is transformed to pinane, while camphene gives two hy- 
drides, a solid melting at 66® and a liquid boiling at 162®.** 

The sodium salts of the two naphthalic acids act differently when 
hydrogenated with copper at 300® under 100 atmospheres. The a acid 
furnishes tetrahydtonaphthalene directly, while the j8 leads first to the 
tetrahydro-naphihalic acid and then to decahydronaphthalene.^ 

Use of Other Metals 

595. Zinc powder can cause the reduction of acetone to the alcohol 
with a yield of 50 %. 

By using palladium, reduced from the chloride by formates, in the 
proportion of 1 g. to 30 g. of the substance to be hydrogenated under 
110 atmospheres at 110®, msthyl-ethyl-acroleine, CiBL.CH :CH(PH»)- 
•CHO, is transformed in 2 or 3 days to msthyl-^ntanol. 

Meaityl oxide is changed in 2 days at 110® to m>ethyl48clnUyUketone. 

By continuous shaking at 110®, cUral is reduced to the decanol with 
a little of the decane. The same may be said of geranioL 

AcetyUacetone, under 116 atmospheres at 109® is changed to pen- 
tanediol in six hours. 

Carbohydrates dissolved in aqueous alcohol are changed to the 

** Ifatibf, /. Rtusian Phy: Chem, Soe,, 38, 75 (1906) and 39, 681 (1907), 
C. A., I, 2877. 

* IPATiBr, /. Ru88ian Phys. Chem. Sac,, 40, 489 (1908), C, 1908 (2), 1098. 

M Ifatdbf, Berichie, 43, 3387 (1910). 

*7 Ifatibf, /. Ruatian Phya. Chem. 80c,, 41, 1414 (1909). 

» IPATnBF, Berichie, 46, 3589 (1913). 

** Ifatibf and Dbachussof, /. Ruseian Phya. Chem. Soe., 4a, 1563 (1911), C, 
Z9ZZ (1), 1292. 



696 CATALYSIS IN ORGANIC CHEMISTRY 212 

corresponding hexites at 110^ under 100 atmospheres. Laevulose yields 
mannite, ghicose goes into sorbite and galactose into dvlcUe.*^ 

IV. HYDR06ENATI0NS BY NICKEL IN LIQUID 
SYSTEMS UNDER LOW PRESSURES 

596. Very extensive use has been made of the common metals, 
particularly nickel, for hydrogenation in liquid medium in the case of 
liquid fats the molecules of which contain ethylene bonds. The de- 
scription of the methods followed and the results obtained is the special 
object of the last chapter but the same process can be generaUzed and 
extended to a large nimiber of cases. The fundamental condition of 
success is a sufficiently energetic agitation in the hydrogen. A pressure 
of several atmospheres is useful but not indispensable, the hydrogena- 
tion being capable of being carried out with even reduced pressure. 
Simply bubbling the hydrogen through the liquid is not sufficient. 

Brochet has tried to define exactly the conditions for using this 
method.'^ 

597. Apparatus. Different forms of apparatus may be used 
according to the amount of the work to be done and the magnitude of 
the pressure to be used. The pressures run from 1 to 50 atmospheres, 
being usually around 10 to 15. 

A red copper autoclave of 1200 cc. capacity, which can operate 
satisfactorily with 700 to 800 cc. of liquid, may be used. The bronze 
cover is fitted accurately and made tight with lead foil packing, being 
held in place by screw clamps. It is fitted with a thermometer-well 
dipping into the liquid, a pressure gauge, and a valve for the intro- 
duction of the hydrogen. The apparatus is heated electrically by a 
ferro-nickel coil insulated by asbestos and surrounded by sheet asbestos 
to keep the heat in. After the introduction of the liquid to be hydro- 
genated, either alone or in solution, and the addition of the catalyst, 
the autoclave is closed and connected with the hydrogen tank which 
is placed along side on the platform of a mechanical shaker. When 
the operation is finished, the catalyst is filtered off and may frequently 
be used immediately for another hydrogenation." 

Brochet uses a 500 cc. glass cylinder connected with a hydrogen 
tank by means of a bubble counter which measures the amount of hy- 
drogen absorbed, and enables one to follow the course of the reaction. 

*^ Ipatiep, /. Rtusian Phys, Chem. Soe., 44, 1002, and 1710 (1912); C. A., 7, 
ZZ7X, and Berichte, 45, 3218 (1913). 

» Bbochbt, BvU. Soc. Chim. (4), 13, 197 (1913) and 15, 554 (1914). 

" A convenient laboratory apparatus with high speed stirring has been de- 
scribed by RjBn>, /. Amer. Chem. Soc,, 37, 2112 (1915). — E. E. R. 



213 LIQUIDS IN CONTACT WITH METAL CATALYSTS 698 

598. Catalysts. The nickel used is prepared by reducing at about 
300° the oxide prepared by calcining the carbonate, nitrate or oxalate. 
After cooling in a current of hydrogen, the reduced metal is plunged 
quickly into the liquid to be hydrogenated, avoiding contact with the 
air as much as possible. 

The nickel may be used alone as a metal powder or incorporated 
with inert materials such as infusorial earth, pumice, or charcoal (126). 
This incorporation with a carrier is advantageous and gives, on re- 
duction at 450°, a catalyst which is more active than the metal alone 
reduced at 350°, and a fortiori more active than the metal alone 
reduced at 450°.» 

Nickel on a carrier is much less sensitive to toxic agents than 
nickel alone. Thus for the metal alone, the amoimt of hydrogen sul- 
phide required to kill the catalyst is 0.02-0.005 g. to 0.5 g. of the 
catalyst, according to the method of preparation, but may be as high 
as 0.1 g. for the metal on a porous support.'^ 

We have seen (584) that Ipatief has found it advantageous with 
his method to use an oxide of nickel, such as NiO or Ni203, in place of 
the metal, and that he considers the oxide more active. The same 
substitution has been proposed for the hydrogenation of oils (943), in 
which the oxides should show a greater activity and should be less 
susceptible to the action of poisons, particularly sulphur.'* But in all 
cases the activity of the oxide may be explained by assuming that it 
is partially reduced to the metallic state, the metal being more active 
on account of being formed within the liquid and in a better state of 
subdivision. This is the opinion of Brochet, who considers the presence 
of the free metal necessary for hydrogenation but thinks that it is 
activated by the presence of foreign substances, such as its oxide, or 
salts or even other metals.'* 

The presence of metallic nickel in the oxide which is used as cat- 
alyst has been denied by Erdmann, who bases his conclusion on the 
absence of conductivity in the catalyst after it has been freed from 
fatty material. 

At any rate, it is well established that at the temperature at which 
the hydrogenation of oils is carried on, nickel oxide is reduced to the 
suboxide, Ni40, which is necessarily slowly reduced at these same 
temperatures to the free metal, the presence of which is easily shown 
by the direct formation of nickel carbonyl by the action of carbon 

" Eblbbr, Beriehte, 49, 55, (1916). 

M Kblbbb, BeriehU, 49, 1868 (1916). 

*• BsDFORD and Ebdmann, /. prakt. Chem. (2), 87, 425 (1913). 

M Bbochbt, Btdl. Soc. Chim. (4), 15, 770 (1914). 



099 CATALYSIS IN ORGANIC CHEMISTRY 214 

monoxide below 100^.'' Meigen and Bartels,'* Norman and Pung^,^ 
and later Frerichs, who found an appreciable conductivity in the oxide 
which had served for the hydrogenation of oil,^ have com# to the 
same conclusion, that is, that the oxide is inactive in hydrogenation, 
the activity belonging only to the free metal. 

Erdmann has claimed that the most active factor in hydrogenation 
is a suboxide, such as NisO, which would form an unstable hydride 

/NiH 
with hydrogen, e.g. 0^ ^ , which is capable of transferring hydro- 
gen to the molecules which can take it up. This special aptitude of 
the suboxide has been claimed by Senderens and Aboulenc, according 
to whom acetone can be hydrogenated at 110^ under 30 atmospheres 
pressure by the suboxide but not by the metal. ^^ 

The amount of catalyst may be as low as 0.5 % of the liquid to be 
hydrogenated, but it is better to use larger amounts in order to hasten 
the reaction.^ 

599. Method of Work. It is best to operate at least 20"^ below the 
boiling point of the liquid used as solvent so that its vapor will not 
dilute the hydrogen too much. If substances are hydrogenated with- 
out solvent, 100 to 150^ is the usual range of temperatures but some- 
tunes from 150 to 200°. 

Alcohol, more or less diluted, and acetic acid are the most favor- 
able solvents. Benzene, acetone, ether, and ethyl acetate are not so 
good, while chloroform is rather harmful.^ 

The course of the reaction is easily followed, either by the pres- 
sure gauge or by the bubble counter, which shows directly the volume 
absorbed. This enables one to see at what temperature the reaction 
goes best. 

600. Results Obtained. Niiro derivatives are readily changed to 
the corresponding amines. Azo and hydroazo compounds are split 
into two amines; but by operating in the presence of caustic soda 
which moderates the action of the catalyst, it is possible to obtain 
azoxy, azo, hydrazo and finally amino from aromatic nitro compounds.^ 

*' Sabatieb and EsnL^ Compt. rend,, 158, 674 (1914). 
" Mbigbn and Babtbls, /. prakt. Chem. (2), 89, 296 (1914). 
» NoBMAN and Pukos, Chem. Zeit,, 39, 29 (1915), C. A., 9, 1562. 
*^ Fbbbichs, Arch. Pharm., 353, 512 (1915). 
^ Sbndbbbns and Aboulbnc, BuU. 80c. Chim. (4), 17, 14 (1915). 
^ In hydrogenatmg cotton seed oil, 0.1 % nickel on a carrier is ample and even 
0.01 % g;ive8 fair results. — E. £. R. 
« Kblbbb, Berushte, 49, 55 (1916). 
M Bbochbt, BuU. 80c Ckim. (4), 15, 554 (1914). 



215 UQUIDS IN CONTACT WITH METAL CATALYSTS 601 

601. Ethylene Double Bonds. These are easily saturated at low 
temperatures, even in the cold, with the evolution of heat. 

A mixture of ethylene, with hydrogen in excess, is changed to ethane 
by being passed at atmospheric pressure through a saturated hydro- 
carbon in which a nickel catal3rst is kept in suspension by rapid 
stirring.** 

a-Octene, treated in alcohol solution with 20 % of active nickel and 
hydrogen at 15 atmospheres, is completely changed to octane in the 
cold. This can be accomplished under atmospheric pressure but takes 
much longer.** 

Oleic add is reduced to stearic add at 250° with a velocity which 
is nearly proportional to the pressure of the hydrogen.*' 

The aliphatic esters. of oleic add are transformed into stearic esters. 

The salt formed by combining hot oleic add with aniline is rapidly 
hydrogenated to a brittle solid melting at 76°.** 

Cinnamic add, in twice its weight of amyl alcohol, is completely 
changed to phenylpropionic in 45 minutes by 10% of nickel at 100° 
under 15 atmospheres. The fact that the acid attacks the nickel does 
not hinder the reaction. However, it is better to use sodium dnnamate 
in 4 parts of water, which is hydrogenated in the cold. 

Methyl dnnamate, dissolved in methyl alcohol, is changed to methyl 
phenylpropionate ** in the cold in 3 hours under 15 atmospheres pres- 
sure. Under ordinary pressure the action is much slower, the reduc- 
tion of ethyl dnnamate requiring 7 hours at 70°.*^ 

Anethol, CHsO.CeH4.CH :CH.CH», is rapidly transformed into 
methoxy^propyl-bemene when treated without solvent with 10% of 
nickel at 60-80° under 15 atmospheres, but requires 5 times as long 
at 1 atmosphere. 

Isoeafrol, dissolved in 3 parts of alcohol with 19 % of nickel, adds 
Hs in an hour at 65°. 

Geraniol and linalool saturate their double bonds, but allyl alcohol 
does not at 70° under 15 atmospheres, neither does allyl avlphocyanaie. 
PiperonyUacrilic acid gives jriperonyUpropionic acid in the cold under 
15 atmospheres.*^ 

The acetylene triple bond is also saturated without difficulty. 

^ Rathbb and Rbu), J. Amer. Chem. Sac., 37, 2115 (1016). 
^ Bbochbt and Bavkr, BvXL. 80c. Ckim. (4), I7» 50 (1915), and Compt. rend., 
I59> 190 (1914). 

« Shaw, /. Soc Chem. Ind., 33* 771 (1914). 

^ Elus and Rabinovitk, /. Ind. Eng. Chem,, 8» 1106 (1916). 

«• Bbochbt and Bauxb, Loc, cU. 

*^ Bbochbt and Cababbt, Compt. rend,, 159, 326 (1914). 

» Bbochbt and Baubb, BvU. 80c Ckim. (4), 17, 60 (1916). 



602 CATALYSIS IN ORGANIC CHEMISTRY 216 

602. Aldehydes and ketones. Aldehydes and ketones are not 
appreciably hydrogenated under atmospheric pressure. Thus the 
aUyJrketanes dissolved in 5 parts of alcohol and treated at 60° with 
hydrogen under atmospheric pressure are hydrogenated in several 
hours to the scUurated ketones without affecting the ketone group.** 

On the contrary, by working under pressure it is possible to change 
aldehydes and ketones to the corresponding alcohols." 

603. Various Rings. The hydrogenation of the benzene ring or of 
similar rings is much more difficult to attain and is scarcely realizable 
except in the case of phenols and of compoimds directly related to 
them.** 

With ordinary phenol the addition of hydrogen takes place slowly 
from 50° up and rapidly between 100 and 150° under 15 atmospheres, 
with complete transformation into cydohexanol without the simul- 
taneous production of cydohexanone. 

Likewise several hours are sufficient for the hydrogenation of a- 
and P-naphthols at 150° under 15 atmospheres. 

Eugenol, CH,0(OH)C«H,.CH,.CH :CH,, adds H, rapidly at 60° 
and 15 atmospheres to form propyUmeAoxy-phenol but the ring is not 
hydrogenated unless the operation is carried on at 150°. 

Indigotine. Indigo, dry or in paste, suspended in water containing 
a little caustic soda (10 g. indigo to 250 c. dilute caustic soda) is 
reduced at 70° by 5 g. nickel to indigo white in 40 minutes. The same 
reaction applies to thunindigo and to malachite green which is reduced 
to the leuco base." 

Hydrogenations by nasc^it Hydrogen in Liquid Ssrstems in 

contact with Metals 

604. The decomposition of formic add by the catalytic action of 
metals of the platinum group provides hydrogen (824) which can be 
used in the liquid itself to effect hydrogenations. By the use of 
spongy or colloidal palladium, dnnamic acid can be transformed into 
phenylacetic or quinine into hydroguinine,^ 

" CoRNUBEBT, Compt. rend., 159, 78 (1914). 

■s Bboghbt and Cabaret, Compl, rend,, 1599 326 (1914). * 

^ The hydrogenation of naphthalene is thoroughly described by Sheobteb, 
Annalen, 426, 1, (1922). — E. E. R. 

** Brochst, Compi. rend,, 160, 306 (1915). 

■* Vbrbin. CmNiNFABR. ZnooBR & Co., Oerman patent, 267,306, 1914, C, 1914 
(1), 88. 



CHAPTER XIII 

VARIOUS ELIMINATIONS 

§ I. — ELIMINATION OF HALOGENS 

605. Thb classical method for the elimination of halogens from 
chlorine, bromine or iodine compomids is treatment with sodium.^ 
The presence of benzene or petroleum ether retards this reaction greatly, 
but ordinary ether and ethyl acetate usually accelerate it.* The use 
of small amounts of aceUmUrUe greatly facilitates the reaction. Thus 
sodium does not act on methyl iodide in the cold but the addition of 
one or two drops of acetonitrile causes an immediate and abundant 
evolution of ethane, CHs.CHs. 

The same is true with ethyl, propyl, ieopropyl and allyl iodides, frt- 
methylene bromide and benzyl chloride. Ethyl cyanide produces a similar 
catalytic effect and propyl cyanide is less effective while benzonitrile 
and benzyl cyanide have no such effect.' 

§ 2. — ELIMINATION OF NITROGEN 

606. Diazo Compounds. In many important reactions of aro- 
matic diaso compounds, a molecule of nitrogen is eliminated. Cu" 
proue aaUe are frequently useful or indispensable catalysts for these 
decompositions. Copper powder can produce the same effects, doubt- 
less through the initial formation of cuprous compounds. 

Diazcbenzene hydroxide, CeH^.N :N.OH decomposes immediately 
even at 0^ in the presence of copper powder to form phenol and nitro- 
gen. The copper for this purpose is precipitated by zinc dust in a 
satiu^ted solution of copper sulphate, washed with water and then 
with a very dilute solution of hydrochloric acid and preserved wet 
and protected from the air.^ 

607. Hydrochloric acid reacts with diazo chlorides, on boiling, to 
give the corresponding aromatic chloride, on condition that the de- 

1 WuBTS, Ann. Ckim. Phv%. (3), 44, 275 (1855). 

* Elbs, SynJth. DarM. d. KMmal,, Leipzig, 1889, a, 59. 

* MicHAXL, Amer. Chem. Jour., 2$, 419 (1901). 
« QATTUUiAKK, BeridUs, 23, 1220 (1890). 

217 



608 CATALYSIS IN ORGANIC CHEMISTRY 218 

composition takes place in the presence of capper powder or cuprous 
chloride^ We have: 

CeHi.Ns.Cl + HCl - N» + C«H..C1 + HCl. 

The cuprous chloride is used in hydrochloric acid solution. 

This action of cuprous chloride has been explained by assuming 
that it acts in the presence of hydrochloric acid as a reducing agent 
giving cupric chloride and hydrogen: 

2CuCl + 2HC1- 2CuCli + 2H 
and 2H + CeHs.N : NCI- CeHs.NH.NHCl. 

The hydrazine compound thus formed reduces the cupric chloride : 
2CuCl, + CflPfi.NH.NHCl - 2CuCl -h 2HC1 -h CeH.Cl + N,. 

teflenorated 

The regenerated cuprous chloride repeats the same effects. 

608. Hydrobromic acid reacts in a similar way on diazonium 
bromides in the presence of cuprous bromide. The cuprous bromide is 
prepared by warming 20 g. copper turnings with a solution of 12.5 g. 
copper sulphate and 36 g. potassium bromide in 80 cc. water con- 
taining 11 g. sulphuric acid.* 

609. Diazonium salts in water solution with sodium nitrite, in 
the presence of copper powder or moist cuprous oxide, are transformed 
into nitro compounds (Sandmeyer reaction): 

CeHft.Ni.Cl + NaNO, - CeHs.NO, + NaCl + Ni. 

610. Diazonium salts yield the corresponding aromatic isocyanates, 
CeHft.NCO, when treated with potassium isocyanate in presence of 
copper powder.'' 

611. Hydrazine Compounds. PhenyUtydrazine i& decompoaed s^t 150^ 
into aniline, nitrogen and ammonia, on contact with cuprous chloride, 
bromide, or iodide: 

3CeH6.NH.NH, - 3C«H5.NH, + N, + NH,. 

The chloride acts more rapidly than the bromide and this more 
rapidly than the iodide. When more than 1% of the chloride is 
added, the decomposition is violent and almost explosive. The crys- 
tallized compound, CuI.2C6H6.NH.NH2, which may serve as an 
intermediate step in the catalysis, has been isolated.^ 

• Sandmbtbr, BerichU, 17, 1635 (1884). 

• Sandmbtsb, BerichU, 17, 2052 (1884). 

' Gattbbmann, BerichU, 33^ 1220 (1890). 

• Arbubow and Tichwinskt, Berichte, 43, 2295 (1910) and /. Rusnoin Phys. 
Chem. 80c., 45, 69 (1913), C. A., % 2225. 



219 VARIOUS ELIMINATIONS 614 

The hydrazonea derived from hydrazine and saturated cyclic ke- 
tones are decomposed, with the evolution of nitrogen, on contact with 
a small fragment of solid potash. 

Cydohexone hydrazone gives cyclohexane in a violent reaction: 

/CHi . CH2\ y/CHi . CHjv 

CH< )C : N .NH, = CH< XH2 + Ni. 

\CH, . CH,/ \CH, . CH./ 

In every case the hydrocarbon obtained contains CHi in place of 
the CO of the ketone. Thus hydrazones from the methyl q/dohexones 
yield methyl cyclohexane, that from camphor furnishes camphane, 
C10H18 melting at 158^, and that from fenchone leads to fenchane, 
boiUng at 151°.» 

612. 3| 6. — Diphenyl-psrrazoline heated with fragments of potash 
and platinized porous porcelain decomposes into nitrogen and diphenyU 
cyclopropane.^^ 

\NH.N^ 



§ 3. — SEPARATION OF FREE CARBON 

613. In many cases the dehydrogenation of hydrocarbons leads to 
the separation of free carbon and we shall see (Chapter XXI) that 
various finely divided metals frequently provoke this decomposition. 
But it is well to consider here a very important reaction which takes 
place with the separation of carbon from carbon monoxide in contact 
with certain substances. 

614. Decarbonization of Carbon Monoxide. In the reduction of 
the oxides of iron, nickel and cobalt carried on above 400^ by carbon 
monoxide, it has long been known that carbon is deposited and this 
continues at the expense of the carbon monoxide according to the 
equation : 

2C0 - CO, + C. 

Mond found that nickel can produce this effect between 350 and 
450°." 

Sabatier and Senderens have shown that the reaction takes place 
with red%bced nickel above 230°, elevation of temperature accelerating 
the decomposition of the carbon monoxide. With a layer of nickel 

* EiZHNSB, /. RuB9ian Phys. Chan, 80c,, 43^ 582 (1911), C. A., 6, 347. 
^« KiZHNSB, /. Ruarian Phys, Chem, Soc., 47, 1102 (1915), C. A,, 9, 3051. 
" MoNB, Langbb and Qxtincki}, Chem, News, 62^ 95 (1890). 



616 CATALYSIS IN ORGANIC CHEMISTRY 220 

35 cm. in length and a flow of gas of 25 cc. per minute, the amounts 
of carbon dioxide formed from 100 cc. of the monoxide were: 

At 238** 1.2 cc. 

250^ 3.8 

275^ 17.9 

285^ 23.2 

300*^ 40.5 

320** 49.0 

349^ and above 50.0, complete transformation. 

The reaction may be complete as can be shown by experiment; and 
besides, the inverse formation of carbon monoxide from carbon and 
the dioxide does not begin below 400^. We do not have to any extent : 

C +C0, -2C0, 
nor: Ni + CQ, - NiO + CO. 

This would take place no more at higher temperatures, such as 
650^ and 800^" 

615. Reduced cobalt gives rise to the identical reaction at above 
300^ 

Finely divided iron, kept at 445^ with carbon monoxide for several 
hours, transforms it completely into carbon dioxide with the deposition 
of carbon." 

Finely divided platinum, reduced copper, and finely divided silver, 
do not produce a similar effect on carbon monoxide below 450^. 

616. The separation of carbon can be explained by assuming the 
temporary formation of nickel or cobalt carbonyl which the high tem- 
perature decomposes into metal, carbon, and carbon dioxide. ^^ 

But we can explain the phenomenon equally well by the mechan- 
ism which is apparent in the case of iron. At low temperatures, iron 
tends to reduce carbon monoxide to carbon with the formation of 
ferrous oxide: 

Fe + CO - FeO + C, 

but at a higher temperature, there is the formation of carbon dioxide 
and iron: 

FeO + CO - COi + Fe. 

The iron thus regenerated can repeat the first reaction. These two 
successive steps may take place likewise with nickel and cobalt without 
our being able to perceive the intermediate compound, the oxide, since 

u Sabatibb and Sbndbbbnb, BvU. 8oc. Chim. (3), 29, 294 (1903). 
" BouDOUABD, Ann. Chim. Phy$. (7), 34, 5 (1901). 
u Bbbthbijot, Ann. Chim. Phy$. (6), a^ 660 (1892). 



221 VARIOIJS ELIMINATIONS Ml 

the reduction of the oxide by the carbon monoxide takes place at a 
temperature lower than that at which the metal reduces the gas, the 
oxide of the metal can remain only in inappreciable amount. From 
this it can be seen that the reaction will taJce place better with nickel 
than with iron, since a considerable proportion of the iron is actually 
transformed into the oxide. ^^^ 

617. Manganous oxide, which dehydrogenates alcohols after the 
manner of metals (701), appears to give, doubtless by a mechanism 
analogous to that which has just been described, a certain amount of 
decomposition of carbon monoxide into carbon and carbon dioxide, 
but it is always small below 350^.^* 

§ 4. — ELIMINATION OF CARBON MONOXIDE 

618. The decomposition of aldehydea and keUmea can take place 
as a consequence of the elimination of carbon monoxide under the in- 
fluence of catalysts, either finely divided metals or anhydrous oxides 
acting at higher temperatures. 

With (Udehydea the reaction goes more readily and yields chiefly: 

R.CO.H - CO + RH. 

hardxooubon 

619. Reduced nickel acts energetically above 200°. The vapors 
of propionic aldehyde are rapidly dissociated at 235° into carbon mon- 
oxide and ethane. Bemaldehyde is largely decomposed at 220° into 
benzene and pure carbon monoxide. ^^ 

Fvrfural is changed by nickel at 270° into fvrftarane^* : 

CH:CHv CH:CH 






CH : G-^HO CH :CH/ 

620. With ketones the result is more difficult to obtain. Starting 
with a ketone R.CO.R' a certain amount of the hydrocarbon R.R' 
may be formed but the d6bris resulting from the groups R and R' are 
the chief products. 

Acetone is decomposed by nickel, slowly at 240° and rapidly at 
270°, yielding carbon monoxide and the CHs radicals which give a 
little ethane and ethylene but chiefly methane, hydrogen and carbon.^'' 

621. Reduced copper has less effect: at 310° its action on propi- 
onic aldehyde is negligible and it is only at 350° or better at 400° that 

" Sabatibb and Sbndbbbnb, Ann. Ckim. Phy$. (8), 4* 485 (1906). 
^* Sabatibb and Mailhb, Ann. Chim. Phy$. (8), ao» 316 (1910). 
^* Sabatibb and Sbmdbbbns, Ann. Ckim. Phye. (8), 4* 474 (1906). 
» Padoa and PoMn, Linon, 15 (2), 610 (1906), C, 1907 (1), 570. 



622 CATALYSIS IN ORGANIC CHEMISTRY 222 

carbon monoxide and a mixture of ethane, hydrogen and biUane is 
obtained.^' Its action is energetic on formaldehyde which it decom- 
poses ahnost completely into carbon monoxide and hydrogen." The 
resulting carbon monoxide can be absorbed by caustic soda present in 
the mixture and furnish, according to a well known reaction, sodium 
formate.^^ 

Copper has no appreciable effect on ketones below 400^. 

622. Platinum sponge and particularly pUiHnum black have an 
intense destructive action on aldehydes. Propionic aldehyde is 
attacked at 225^, and at 275° decomposes rapidly into the same gas- 
eous products as are obtained with copper.'^ 

The action on ketones is less intense. 

623. At 300° palladium black decomposes formaldehyde completely 
into carbon monoxide and hydrogen with traces of carbon dioxide and 
methane. Likewise acetaldehyde, propionic aldehyde, butyric aldehyde, 
benzaldehyde, and the toluic aldehydes are more or less split at temper- 
atures around 300° into carbon monoxide and the corresponding 
hydrocarbons." 

624. The decomposition of formic add into carbon monoxide and 
water which is effected by certain oxides, titania, blue oxide of tungsten, 
alumina, silica, and zirconia, and which can be regarded as an elimina- 
tion of carbon monoxide, will be studied later (825), as also the 
decomposition of formic esters, which is chiefly according to this 
reaction (866) : 

H . C02Ci|Il2n4.i = CO + CnHjn+i.OH. 

625. Anhydrous aluminum chloride can decompose acid chlorides 
with the elimination of carbon monoxide. This takes place with 
dichloracetyl chloride which is split into carbon monoxide and chloro- 
form with heptachbrpropane as a by-product, resulting from the action 
of the chloroform on the original product." 

§ 6. — ELIMINATION OF HYDROGEN SULFHIDB 

626. Mercaptans. Cadmium sulphide catalyzes the decomposition 
of m^captans according to two consecutive reactions exactly analo- 
gous to those according to which a primary alcohol is dehydrated to an 
ether and then to an imsaturated hydrocarbon (701). 

^* Sabatebb and MAn^EOS, Ann. Ckim. Pkys, (8), ao, 345 (1910). 

w LoBW, Berichte, ao, 145 (1887). 

'^ Sabatibb and Sbndbbbns, Ann. Ckim. Pkys. (8), 4, 475 (1905). 

** EuzNBZov, /. Russian Pkys, Chem. Soc., 45, 557 (1913). 

» Puns, /. prakt. Chem. (2), 89, 414 (1914). 



223 VARIOUS ELIMINATIONS 628 

At a moderate temperature, we have: 

2CnHsB+l.SH = H2S + (CnH2n-n)2S. 

sulphide 

At a higher temperature, a more rapid decomposition yields hydro- 
gen sulphide and the ethylene hydrocarbon: 

Thus ethyl mercaptan, CsHs.SH, passed over cadmium sulphide at 
320^, is almost completely transformed into the neutral sulphide, 
(CsHt)2S, while at 380^ it is completely decomposed into hydrogen 
sulphide and ethylene. 

laoamyl mercaptan is changed into isoamyl sulphide at 360^, but 
above 400^ gives hardly anything but amylene. 

The decomposition of prirmry aliphatic mercaptana over cadmium 
sulphide at regulated temperatures constitutes a regular method of 
preparing primary sulphides from the mercaptans. 

627. The mechanism of the decomposition is altogether analogous 
to that of alcohols (169). We can assume the formation of a cadmiimi 
mercaptide from the mercaptan and cadmiimx sulphide. This would 
decompose, according to the temperature, either into the neutral sul- 
phide or into the ethylene hydrocarbon with the regeneration of the 
metal sulphide which would then repeat the reaction, thus playing 
the part of a catalyst. 

We have at first: 

CdS + 2CnH2n+l .SH = (CnH2n-nS)2Cd + HjS 

mercaptide 

then: 

(CnHto+iS),Cd = CdS + (CnH^n-fOaS 

Bulphide 

and at a higher temperature: 

(CnHto+lS),Cd = CdS + H,S + 2CaH2a. 

The transitory formation of the cadntuum mercaptide is further 
indicated by the change of color of the sulphide, which takes on an 
orange tint quite different from the bright yellow of the original 
sulphide and retains that color after cooling in consequence of the 
persistence of a certain amount of the mercaptide. 

628. Secondary mercaptans have a stronger tendency to decom« 
pose into the ethylene hydrocarbons but can, nevertheless, furnish 
some neutral sulphide. 

Cydohexyl mercaptan, passed over cadmium sulphide at 300^ gives 



629 CATALYSIS IN ORGANIC CHEMISTRY 224 

12 to 15% of the sulphide but the major portion is decomposed to 
cyclohexene, while at 350® all of it goes into cyclohexene.** 

629. Thiophenols. Aluminum chloride acts on a warm solution of 
thiophenol in petroleum ether, eliminating hydrogen sulphide and 
forming the diphenyl sulphide. At the same time some thianthrene, 

C6H4. yCeHi, is formed by loss of hydrogen.** 

630. Formation of Thioureas. The thioureas can be obtained by 
the reaction of primary aromatic amines on carbon disulphide in the 
presence of a little sulphur as catalyst. 

Thus 1 part each of aniline, alcohol, and carbon disulphide and 
0.005 part cryBtallized sulphur are warmed for several hours on the 
steam bath to obtain qmtmietrical diphenyl-thiourea : 

/NH.CeHfi 
OS, + 2C6H6NH, = H2S + CSC 

NNH.CeH. 

The ortho and para toluidineSf the naphihyl-amines and even 
p Mminophenol give the same reaction.^ 

§ 6. — ELIMINATION OF AMMONU 

631. Reduced nickel has various effects on primary, secondary, 
and tertiary amines, and among these effects one is the elimination of 
ammonia.^ 

Above 300® this is a clean cut reaction with aliphatic amines con- 
taining less than 5 carbon atoms. Thus ethylamine splits up into 
ammonia and ethylene, which at that temperature is in turn decom- 
posed into carbon, methane, hydrogen and ethane (910). We have: 

CH5.NH»-NHi + aH4. 

Amines containing five or more carbon atoms, e.g. amyUamine, 
undergo this reaction and are simultaneously dehydrogenated to 
nitriles. This is true for benzyl-amine also.** 

Aromatic amines, aniline and the toluidines, are much more resist- 
ant, being hardly attacked by nickel at 350®, but towards 500® there 
is elimination of ammonia with complete destruction of the molecule, 
according to a complicated reaction.** 

^ Sabatibb and Mmlhb, Compt, rend,, 150, 1570 (1910). 
" Dsuss, Bee. Trav. Chim. Pay9-Baa, 27, 145 (1908). 
^ HuGBRSHOFF, BerichU, 339 2245 (1899). 
*^ Sabatobb and Gaudion, Campt, rend,, 165, 309 (1917). 
** Sabatibb and Gaudion, Compt. rend., 165, 226 (1917). 
** Sabatibb and Gaudion, Cempt. rend., 165, 309 (1917). 



225 VARIOUS ELIMINATIONS 633 

632. By heating a-maphthylamine for 8 hours with a molecule of 
aniline in presence of a small amount of iodine (\eas than 1 %), am- 
monia is eliminated and phenyhmaphthylamine is formed in 85% 
yield. 

The use of very small proportions of iodine enables us to prepare 
the secondary amines derived from a-naphthylamine and the three 
tolmdines, ortho and para anisidines, and meta and para chlaranilinea, 
with yields superior to those obtained by the usual methods. 

By heating ^-napkthylamine on the steam bath for 4 hours with 
less than 1 % of iodine, it is almost quantitatively changed into /3/3'- 
dinaphthyl-amine. 

Likewise p .aminaphenol heated below 200^ for 5 hours with 
0.0025% iodine, loses anunonia and yields about 70% pp' .dihydroxy^ 
diphenylamine}^ 

633. Cuprous chloride and bromide and also zinc chloride catalyze 
the decomposition of the phenyUiydrazones derived from the lower 
aUphatic sJdehydes and ketones, giving ammonia and substituted 
indole. 

Thus the phenylhydrasone of methyUethyUketone evolves ammonia 
at 180^ when 0.2 % of cuprous chloride is added and yields t, S-di- 
methyhindol in 2 hours. 

The phenylhydrazone of propionic aldehyde gives similarly S^meth" 
yJrindol (skatol). With copper chloride the yield is 60% and reaches 
73 % with zinc chloride. 

With aldehydes there is some formation of nitriles resulting from 
splitting off aniline (635). 

The formation of /3-methyl-indol is thus represented: 

H(x x;h CH HC^ ^C C-CH, 



In the same way, the phenylhydrazone of acetonyUacetone yields 
dimefhylramino^henyUpyrroU^ 

With the phenyUiydrazones derived from higher aliphatic alde- 
hydes, this reaction is of little importance as it is overshadowed by the 
formation of nitriles (635). 

•• Enobtbnaobl, J. prakt. Chem. (2), 89, 20 (1914). 

"^ Abbubof and Tikhvinbkt, /. Ruatian Phut. Chem. 8oe.f 45, 73 (1913), 
C. A., 7, 2225. — AsBUSOF and Fbiauf, Jhid., 45, 694 (1913), C. A., 7, 3599. — 
AsBUSOF and EBBurzKn, Ihid., 45, 699 (1913), C. A., 7, 3599. 



634 CATALYSIS IN ORGANIC CHEMISTRY 226 

§ 7. — ELIMINATION OF ANILINE 

634. The stability of aniline in the presence of nickel, which has 
been mentioned above, enables us to predict that the action of nickel 
on alkyl anilines will tend to split off aniline, as ammonia is elimi- 
nated from the alkyl ammonias. This is what takes place with methyU 
aniline at 250°. Aniline is regenerated with the separation of the 
group CHs which decomposes into methane and carbon, the reaction 
being nearly thus: 

2CeH5.NH.CH, - 2C«H..NH, + C + CH.. 

With eihyl-aniline, we have: 

COi.NH.CHs - C«H..NH, + CH4, 

the ethylene being entirely decomposed by the nickel (912) into carbon, 
methane, ethane and hydrogen, the hydrogen acting on the aniline to 
give a little ammonia and benzene. 

Dimethyl-aniline and cHeihyUanUine behave in an entirely anal- 
ogous manner.** 

635. The phenylhydrazones of higher aliphatic aidehydea are de- 
composed by copper, ziric, and platinum chlorides into nitrUes and 
aniline : 

R.CH :N.NH.C«H6 - R.CN + CeH.NH,. 

This is true for iecbyiyriCy isovaleric, and isoheptylic aidehydes. The 
simultaneous production of indole (633) is of little importance.** 

** Sabatibb and Gaudion, Compt. rend,, i6$| 309 (1917). 
" Abbusof, /. Ruuian Phys. Chem, Soc., 45, 74 (1913). 



CHAPTER XIV 
DEHYDROGBNATION 

636. Wb have explained direct hydrogenation by means of finely 
divided metals by the formation of an unstable hydride, produced 
rapidly by the metal and capable of readily giving up its hydrogen. 
If this explanation is correct, an important consequence can be 
readily foreseen. The catalytic metals, nickel, copper, and platinimx, 
should be able to take up hydrogen not only from molecules of free 
hydrogen but also from other substances capable of furnishing hydro- 
gen, and consequently to be dshydrogenatian caialysts, a prediction 
which experiment has largely verified. 

637. This capability has been long known in some cases. As 
early as 1823 it was known that iron, copper, gold, silver, and plaUnum 
had the power of greatly facilitating the decomposition of ammonia, 
without appreciable alteration of the metal. The decomposition of 
the ammonia can be thus effected at a much lower temperature than 
in the absence of these metals.^ 

In 1843, Reiset and Millon noticed that alcohol vapor passed 
through a tube filled with fragments of porcelain and heated to ^00^, 
is not appreciably decomposed, but that decomposition manifests 
itself at 220^ in presence of platinum sponge} 

In 1866, Berthelot noticed that the presence of iron favors the 
decomposition of acetylene at a red heat,' and later Schiitzenberger 
stated that platinum sponge warmed in a current of acetylene, decom- 
poses it with incandescence, giving a volimiinous mass of carbon in 
which the metal is diffused.^ 

This active decomposition of acetylene was rediscovered in 1896 
by Moissan and Moureu, who observed it also with recently reduced 
iron, cobalt, and nickel.'^ A similar decomposition of ethylene in con- 
tact with the same metals at 300^, was obtained in 1897 by Sabatier 
and Senderens,* who interpreted it by assmning the temporary for- 

^ DuiiONG and ThAnabd, Ann. Ckim, Phys, (2), 23, 440 (1823). 

* Rbisbt and Mnxox, Ann. Chim. Phys. (3), 8, 280 (1843). 

* Bbbthblot, Ccmpt. rend., 62, 906 (1866). 

^ SchDtzxnbbboeb, TraiU de Chemie, I, 724. 
' * M0188AN and MoTJBBU, Campt. rend., laa, 1241 (1896). 

* Sabatibb and Sbmdbbbns, Compt. rend., 134, 616 (1897). 

227 



638 CATALYSIS IN ORGANIC CHEMISTRY 228 

mation of a metal hydride and were thus led to apply these metals to 
dehydrogenation reactions as well as to those of hydrogenation. 

638. The dehydrogenation catalysts are primarily the metalsy and 
to a less degree, certain anhydroiu metal oxides and some salts derived 
from these oxides, carbon and, in exceptional cases, ankydroue alur 
minum chloride. 

The effects produced by these catalysts can be divided into several 
groups : 

1. Dehydrogenation of hydrocarbons. 

2. Return of hydroaromatic compounds to aromatic with double 
bonds. 

3. Conversion of primary alcohols to aldehydes and of secondary 
to ketones. 

4. Dehydrogenation of poly-alcohols. 

5. Dehydrogenation of amines to nitriles. 

6. Direct synthesis of amines from hydrocarbons. 

7. Formation of rings by loss of hydrogen. 

§ 1. — DEHYDROGENATION OF HYDROCARBONS 

639. Finely divided metals exercise an important dehydrogenating- 
effect on hydrocarbons, the effect being greater the higher the tem- 
perature. The separation of hydrogen is always accompanied by mo- 
lecular changes, which are frequently followed by condensation into 
more complex hydrocarbons. We will return to the breaking down 
and building up of hydrocarbons by catalysts in Chapter XXI, which 
is devoted to that subject, and will content ourselves in the following 
paragraph to the regular passage of hydroaromatic hydrocarbons to 
the aromatic with double bonds. 

§ 2. — DEHYDROGENATION OF HYDROAROMATIC 

COMPOUNDS 

640. The various compounds formed by the hydrogenation of 
stable cyclic compounds tend to revert to the latter by loss of hydrogen 
when submitted to the action of finely divided metals at tempera- 
tures higher than those at which they are formed directly. Among 
the metals, reduced nickel shows itself as particularly active.^ 

The dehydrogenation can take place in the presence of excess of 
hydrogen, and in some cases the excess of hydrogen, far from hinder- 

^ Thi^ ,18 probably a reversible reaction reaching a definite equiHbrium for each 
temperature and pressure of hydrogen. Quantitative studies are most desirable. 
'— £. £. R. 



229 DEHYDROGENATION 642 

ing the reacHan, regulcUes it by favoring the maintenance of the cyclio 
structure and diminishing the tendency to the breaking up of the 
molecule into many fragments (644). 

641. Cyclohezane, which can not be formed by the direct hydro- 
genation of benzene by the aid of nickel above 300^ (446), suffers a 
partial dehydrogenation to benzene above 300^, but a part of the 
benzene is transformed to methane by the Uberated hydrogen: * 

BClsHu - 2C6H6 + 6CH4. 

The presence of a current of hydrogen stabilizes the molecule to a 
certain extent so that it is only slightly broken up at 350^ At 400^ 
about 30 % of the cyclohexane passing over the nickel with the hydro- 
gen is decomposed into benzene.* 

With meOiylrq/dohexane alone, decomposition begins at 240^ and 
is rapid at 275^, the gas evolved then containing: 

Methane 78 % by volume 

Hydrogen 22 % by volume 

The condensed liquid contains a large proportion of toluene. 

Ethylrq/dohexane is attacked slowly at 280 to 300^ and gives a 
gas containing 83 % methane and 17 % hydrogen, a mixture of ethyU 
benzene and toluene being condensed. 

The 1, S-dimethyl-cydohexane acts like cyclohexane and is stabilized 
by an excess of hydrogen. At 400^, the dehydrogenation to m, xylene 
does not exceed 25%.^® 

Reduced copper exercises a similar but less intense action which 
does not begin till above 300^ 

642. Hydroxy and amino substitution products of cyclohexane 
hydrocarbons undergo dehydrogenation still more readily and above 
350^ the reaction is not hindered by an excess of hydrogen. 

In the presence of nickel above 350^, cydohexanol and its homologs 
come back to the phenol condition. This effect commences at even 
much lower temperatures: when cydohexanone is hydrogenated over 
nickel at 230^, 25% of phenol is collected along with the cydo- 
hexanol.^^ In a current of hydrogen at 360^ the transformation into 
phenol is practically complete." 

The same effect is even more important for the cyclic poly-alcohola 
and also for the amines such as cydoheoDylramine which tends to regen- 

* Sabatdbb and Mailhb, Compt. rend., 137, 240 (1903). 

* Sabatibb and Daxtdibb, CampL rend., 168, 670 (1919). 
^* Sabatibb and Qaxtdion, UnpvbUehsd retuUe, 

u SxTTA and Rittbb, BeriehU, 44, 668 (1911). 

^ Padoa and Fabbis, Lineei, 17 (1), 111 and 125 (1908), C, 1908 (1), 1395 and 
1908 (2), 1103. 



613 CATALYSIS IN ORGANIC CHEMISTRY 230 

erate aniline and dicyclohexyJramine which yields diphenylamine and 
q^dohexylanUine. 

The hydrides of naphthalene act in the same way: the higher 
hydrides under the influence of nickel at 200^ come back to the 
tetrahydride, and this regenerates naphthalene at 300^. 

Frequently, as in the case of cyclohexane, the Uberated hydrogen 
can break down a portion of the hydrocarbon into larger or smaller 
aliphatic fragments. This takes place with dodecahydrophenanthrene, 
which breaks down at 200^ into lower hydrides and various aUphatic 
hydrocarbons, while the hexahydride is regularly dehydrogenated to- 
the ietrahydride at 220^, which in turn passes to phenanthrene at 280^. 

V^th nickel at 300-330^, the perhydrides of anthracene give the 
tetrahydride and decomposition products 

At 250^, decahydrofiaorene returns to fluorene. 

643. Unsaturated cyclic hydrocarbons, cydohexenes, cydohexadi- 
enea, as well as the terpenea and various of their substitution products, 
are still more readily dehydrogenated by nickel even in a current of 
hydrogen. 

Cydohexene gives benzene almost quantitatively when passed over 
nickel at 250°." The same is true at 300** in a current of hydrogen." 

Cydohexadieney CeHg, passed over finely divided platinimi at 180^ 
yields benzene, but this is mixed with cydohexane, which is stable at 
this temperature and which results from the utilization of the liberated 
hydrogen." 

644. Limon^iei in a current of hydrogen over nickel at 280-^00°, 
is changed almost entirely into cymene accompanied by a certain 
amount of cumene and simpler aromatic hydrocarbons. 

MenOiene, in hydrogen over nickel at 360**, yield 80 % of cymene. 
Under the same conditions, pinene and camphene are dehydro- 
genated to aromatic hydrocarbons, CioHu and lower. ^^ 

y'CHj . CHjN. yCHf 

646. Eucalyptoly or cineol, CHs . C XJH . C(^ , carried 

|\CH,.CH,/|\CH, 

along by a current of hydrogen over nickel at 360° is simultaneously 
reduced and dehydrogenated to form cymene. 
Terpineol undergoes a similar reaction. 

Pulegone, CHj . CH^ yC : C. , submitted to the action 

^CHa.CHj/ \CH, 

" Sabatudb and Qaudion, Campt, rend., 1681 670 (1019). 
i« B^BSBKBN, Ree, Trav. Chim. Payw-Bas, 37, 266 (lOlS). 
^ Sabatdb^ and GAyniON, Campi. rend.^ x68| 670 (1010). 



231 DEHYDROGENATION 649 

of nickel in a current of hydrogen at 360^, is changed into a mixture 
of thymol and cresol, formed by the elimination of the carbon chain 
in the form of methane.^' 

646. Dodecahydrotriikhenylene is completely changed to triphen" 
ylenSf melting at 198^, by passing over copper at 450-500°.^* 

647. Piperidine» under the action of nickel at 180 to 250°, even in 
the presence of hydrogen, is totally changed to pyridine :^^ 

/CHj . CHjv /CH : CHv 

ch/ ;nh -^ CH^^ ^N. 

Tetrahydroquinoline, passed over nickel at 180°, gives a certain 
proportion of quinoline, but the chief product is skatol:^^ 

CH CH, CH 

^ \ / \ ^ \ 
HC C CH, HC C C.CH, 

HC C CH, HC C C] 



^ -^ \h/ \h / V^ 



648. If dehydrogenation is carried out with a partially hydrogen- 
ated product, the hydrogen set free by the action of the metal on 
one portion may hydrogenate the other. This is what takes place 
when paUadium sponge acts on methyl tetrahydroterephthalate which 
gives 1 part methyl terephthalate and 2 parts msthyl hexahydro- 
terephihdkUe.^^ 

649. Palladium black is an active dehydrogenation catalyst for 
the hexamethylene hydrocarbons. The action begins at 170°, is vigor- 
ous at 200°, at a maximum at 300°, and yields only hydrogen and 
benzene or its homologs. At 100-110°, the inverse action takes place, 
i.6. there is hydrogenation of the benzene, but this does not take 
place at 200° even in excess of hydrogen. Likewise hexahydro^ 
benzoic acid passes to bemoic.*^ The esters of hexahydrobemaic acid 
are also dehydrogenated, but methyl cydoperUane-^xurbonate is not 
affected.** 

1* Mannich, BerichU, 40, 159 (1906). 
" CiAMiczAN, Lineeif x6, 808 (1907). 

» Padoa and Scaqliabini, Lincei, 17 (1), 728 (1908), C, 1908 (2), 614. 
!• Zbunbxy and Qunka, BerichU, 44, 2305 (1911). 
^ Zbunbkt and Miss Uklonbkaja, Berichte, 45, 2677 (1912). 
^ Zbunbkt and Mies Uklonbkaja, /. Ruuian Phyt, Chem. 80c. 461 56 (1913), 
C. A., 7, 2224. 



660 CATALYSIS IN ORGANIC CHEMISTRY 232 

Below 300^, cycloperUane and methyUcychperUans*^ and cydohep^ 
tans ^ are not dehydrogenated. 

Platinum black acts similarly but less energetically.^ 

§3. — DEHYDROGENATION OF ALCOHOLS 

650. A long time ago Berthelot noticed that the vapors of ethyl 
alcohol passed through a progressively heated glass tube, begin to 
decompose at around 500^, that is at nearly a dull red heat, giving 
rise to two simultaneous reactions, namely: dehydration with sepa- 
ration of ethylene and dehydrogenaUon with the production of alde- 
hyde, the reactions being further complicated by the decomposition of 
the ethylene and the aldehyde by the heat, the aldehyde being par- 
tially decomposed into carbon monoxide and methane.*^ 

Various primary alcohols undergo analogous decompositions at a 
dull red heat, being simultaneously dehydrated and dehydrogenated. 
We have: 

^HjO -|- Ciili2n+i .CH : CHs 

CnHte^.! . CHf . CHjOH ethylene liydrooMbon"~ 

^ Hj -f- CnHsn+1 • CHj . CO . H 



aldehyde 



and likewise: 



.H^ + (CeH..CH), 

benzyl aloohol ^•HJ + CJ^j^O^ 

bensaldehyde 

Up to 400^, neither of these reactions takes place to any appre- 
ciable extent. 

Secondary alcohols react more readily in this manner, giving hy- 
drocarbans by dehydration and ketones by dehydrogenation, the one or 
the other reaction predominating as the case may be. Thus, for 
secondary aliphatic alcohols, ethylene hydrocarbons are formed rather 
than ketones, while bemhydrol 3rields benzophenone at as low as 290^.*^ 

651. In the presence of catalysts , that is to say of substances capa- 
ble of forming temporary chemical combinations with one of the 
products of the above reactions, the corresponding reaction will be 
realized at a lower temperature and rendered more or less rapid. 

tt Zblinbkt, /. Russian Pkys. Chenu 8oe., 43, 1220 (1911). — BsricfUe, 45, 3678 
(1912). 

1" Zbukbkt and Hsbzbnstbin, /. Russian Phys. Chsm, Soc, 44, 275 (1912). 

M Bebthxlot and Junqfleisch, TraiU Aim, de Chimie Org,, 2nd. Ed. Paris, 
1886, I, 256. 

" ENOKVXNACtKL and HxcKSL, BenchU, 36, 2816 (IWS). 



233 DEHYDROGENATION 66S 

Dehydrogenation eatalysU ehould specially promote the decompo- 
sition of alcohols into aldehydes or ketones, while dehydration catalysts 
should facilitate the formation of water and hydrocarbons. 

The metals, copper, cobalt, nickel, iron, plaJtinum, and palladium, 
particularly in the finely divided form, are dehydrogenation catalysts, and 
so are a small number of anhydrous oxides, e.g. manganous, though to 
a less extent. 

On the contrary, certain metal oxides are exclusively dehydration cata- 
lysts for alcohols : such are thoria, alumina and the blue oxide of tungsten. 

Finally a large number of substances, oxides and salts, have both 
functions and can to very variable extents cause the dehydration and 
the dehydrogenation of alcohols at the same time. Beryllia and 2tr- 
conia play the two rdles almost equally well; all the intermediates 
are found between the two extremes of exclusive catal3rsts.** 

652. Of all the dehydrogenation catalysts, the one that serves best 
for the regular decomposition of primary or secondary alcohols into 
aldehydes or ketones, is reduced copper, which in practice can be 
replaced by the very finely divided copper which is manufactured fo 
imitation gilding. 

Cobalt, iron, and platinum can be used, but with poorer results, 
while nickel is the least suitable.^ 

Use of Copper 

653. Primary Alcohols. Primary aliphatic alcohols, when passed 
in the vapor form over reduced copper kept between 200 and 300^, 
are regularly decomposed into aldehydes and hydrogen, the conden- 
sate containing, along With the aldehyde, some of the unchanged 
alcohol and a Uttle of the corresponding acetal. The practical 3deld 
is usually above 50 % with less than 5 % of higher products and 45 % 
of the alcohol which can be fractioned out and put through again. 
This is a very advantageous method for the preparation of aliphatic 
aldehydes, particularly for those which, on account of low volatility, 
are difficult to prepare by oxidation of the alcohols. 

The transformation can never be complete, even when a long train 
of copper is used, since the hydrogen which is formed can be added to 
the iddehyde by copper above 200^. Hence the reaction is limited but 
the conditions are favorable to the decomposition because the operation 
is carried on in the presence of a small concentration of hydrogen. 

By operating under reduced pressure, there is the double advan- 
tage of a more ready volatilization of the alcohols and a diminution 

>• Sabatibb and Mailhb. Ann, Ckim, Phys. (8), 30, 289 and 341 (1310). 
^ Sabatibb and Sbzvdbbbnb, Compi. rend., 1361 738, 021 and 083 (1903). 



664 CATALYSIS IN ORGANIC CHEMISTRY 234 

of the reverse action of hydrogen, and consequently increasii^ the 
practical yield. 

654. The apparatus used by Sabatier and Senderens is the same 
as that employed for hydrogenations (347) except that the tube for 
introducing the hydrogen is omitted.'^ 

Bouveault has used a vertical tube for the catalyst, 25-30 mm. in 
diameter and of varying length, up to 1 m. The lower extremity 
which is drawn down to 10 mm. passes through the stopper of a flask 
in which the alcohol is vaporized. The tube is filled with rolls of 
copper gauze containing copper hydroxide, resembling cigarettes; it 
is heated by a coil of resistance wire through which passes a current 
that can be suitably regulated. The reduction of the copper hydrox- 
ide is effected by hydrogen at 300^ and should be carried on slowly so 
as to leave an adherent mass of copper. 

The current is regulated so as to obtain the desired temperature 
and the alcohol vapors pass through the vertical catal3rst tube and 
from it into a fractionating column which separates the more volatile 
aldehyde and returns the less volatile alcohol to the flask to be reva- 
porized. A catalyst tube 1 m. long is sufficient for the preparation 
of 500 g. aldehyde in a day.** *<* 

It is evident that the apparatus may be connected with a pump 
controlled by a regulator so as to operate in a partial vacuum, if this 
is desired. 

655. If the temperature is above a certain point, the aldehydes 
formed are partially destroyed by contact with the metal with elim- 
ination of carbon monoxide : 

R.CO.H -CO + RH. 

But except in the case of formaldehyde and the aromatic alde- 
hydes, this decomposition is not yet rapid at 300^. 

This decomposition is more rapid with a more active catalyst. 
With methyl alcohol, using a light violet copper prepared by the dow 
reduction of the precipitated oxide, there is a rapid evolution of gas 
which contains about 1 volimie of carbon monoxide to 2 of hydrogen: 
the formaldehyde produced has been completely destroyed, only traces 
of it being found in the condensate. We have: 

H.CH2.0H = CO + 2H2. 

On the contrary with compact reddish orange copper, prepared by 
reducing a dense oxide at a dull red, the evolution of gas is only about 

** Sabatdbb and Bbnbbbbns, Ann. Chim. Pku9. (8), 4, 332 (190$. 
*• BoxTVBAUi/r, BvU. Soc Chim. (4), 3, 60 and 119 (1908). 
M This apparatus and its operation are more fully described by Wbibicann and 
Gabrand, /. Chom. Soe.^ 117, 828 (1920). — E. E. R. 



236 DEHYDROGENATION 667 

one twelfth as rapid, but it is practically pure hydrogen and ahnost 
all of the formaldehyde survives.'^ 

656. Methyl alcohol is decomposed even at 200^ and very rapidly 
at 280-300^ 

By catalytic decomposition over copper, methyl alcohol can be 
detected in ethyl alcohol, since the formaldehyde produced can be 
characterized by the violet coloration which it gives with morphine 
and concentrated sulphuric acid.** 

The destruction of the formaldehyde is already apparent at 240- 
260^, hydrogen and carbon monoxide being produced along with a 
little methyl formate (225),'' this destruction increasing rapidly with 
rise of temperature, till at 400^ at least 75 % is decomposed. 

Ethyl alcohol is decomposed above 200^, the aldehyde being formed 
rapidly at 250 to 350^ without complications. At 420^ 16 % of the 
acetaldehyde is destroyed and the gas collected contains 3 volumes 
of methane and 1 of carbon monoxide to 6 of hydrogen.'^ 

Propyl alcohol is transformed regularly at 230 to 300^ and at 420^ 
one fourth of the aldehyde is destroyed. 

Butyl alcohol yields the aldehyde well at 220 to 280"", and at 370'' 
only one sixth is destroyed. 

At 240 to 300^, isobiUyl alcohol is easily transformed into the 
aldehyde : at 400^, one half of this is decomposed. 

Isoamyl alcohol yields the aldehyde at 240 to 300^ without compli« 
cations. At 370^ only 6 % of the product is decomposed and at 430^, 
about 25 %.» 

An aliphatic Cio alcohol is regularly changed into the aldehyde by 
heating in Bouveault's apparatus under reduced pressure.'* 

The copper is never fouled by carbonaceous deposits and remains 
able to continue the reaction indefinitely. 

657. Benzyl alcohol is transformed less readily than the aUphatic : 
the decomposition does not begin below 300^ but is satisfactory there. 
At 380^ the reaction is complex and some toluene and benzene are 
formed along with the benzaldehyde, while the gases evolved contain 
carbon monoxide and dioxide along with the hydrogen. From 18 
parts of alcohol, only 13 go to the aldehyde, the other 5 forming 
benzene and toluene. 

Under reduced pressure, phenylethyl alcohol, CeHc.CHs.CHsOH^ 

^ Sabatibb and MAn<HS, Ann. Ckim. Phya. (8), 30| 344 (1910). 

" Manmich and Qbilmann, Arch. Pharm,, 254, 50 (1916), C. A., ix, 1114. 

" Mannich and Qbiliiamn, Berichte, 49^ 685 (1916). 

M Sabatibb and Sbndbbbnb, Ann. Ckim. Phys. (8), 4» 463 (1905). 

« Babatdbb and Sbndbbbnb, Ann. Ckim. Pkys. (8), 4» 463 (1905). 

M BouvBAUur, BvU. See. Ckim. (4), 3, 50 and 119 (1908). 



0B8 CATALYSIS IN ORGANIC CHEMISTRY 236 

3rields phenyUaceidldehyde readily, but there is a little decompodtion of 
the aldehyde into toluene and carbon monoxide and there is also some 
dehydration of the alcohol to styrenSf C»H|.CH : CHsi the major part 
of which is hydrogenated to eihyUbemene or condensed to the slightly 
volatile metorstyrene which remains on the metal and weakens its 
catalytic activity. 

658. The unsaturated allyl alcohol, CHs :CH.CHsOH, is trans- 
formed over copper at 180 to 300^, with the evolution of very little 
hydrogen, into propionic aldehydej with a slight amount of acroldne. 
llie hydrogen derived from the decomposition of the alcohol serves 
to hydrogenate the double bond of the aldehyde formed (432).*^ 

It is the same way with undecenyl alcohol, CHt :CH.(CHs)8.- 
CHfOH, which yields only the saturated aldehyde, undscenal. On 
the contrary, under reduced pressure, geraniol (416) gives ciiral 
almost entirely.*^ 

669. Secckadary Alcohols. The transformation of secondary alco- 
hols into ketones with the separation of a molecule of hydrogen is even 
more readily accomplished by finely divided copper since, the ketones 
being more stable than the aldehydes, a larger temperature interval 
is available in which to effect the transformation. Usually even at 
400^ there is no appreciable complication, the gas evolved is pvre 
hydrogen. The immediate yield of ketone may exceed 75%. 

As in the case of the aldehydes, the reaction is never entirely com- 
plete, since, in contact with copper above 200^, the disengaged hydro- 
gen is capable of hydrogenating the ketone to regenerate the alcohol. 
But the hydrogenating power of the copper is much less than its 
aptitude to decompose the alcohol and the production of ketone pre- 
dominates greatly.'^ 

leopropyl alcohol is decomposed slowly from 150^ the production 
of acetone being rapid at 250 to 430^, without separation of propylene. 

Secondary bulyl alcohol is attacked at 160^, and furnishes butanone 
readily at 300^ without production of butylene. 

Secondary odyl alcohol produces only the octanone{£) at 250 to 
300^ It is only above 400^ that there is decomposition into carbon 
monoxide and hydrocarbons. 

660. Over copper at around 300^ cydohexanol is split cleanly into 
hydrogen and cyclohexanone.'^ 

At 300^, o.methylrcydohexanol is transformed into o.methylrcydo' 
hexanone, with a little water and o.meihyUcydohexene and some 
o.creeol which are readily eliminated. Results almost as good are 
obtained with the meta but less satisfactory with p.methylrcyclohexanoL 

^ Sabavibb and Bbndbbsnb, Ann. Ckim. Phya. (8), 4, 467 (1905). 



237 DEHYDROGENATION 664 

The method may be used with the same facility with the various 
dimethylrcydohexanoU.*^ 

661. By contact with copper at 300^ bamsol is changed very 
readily and almost totally into camphor}^ 

662. Benzhydrol. C6H6.CH(OH).C6Ht, when its vapors are 
passed over copper at 350^, yields benzaphenane, which is largely 
changed by the liberated hydrogen into diphenylrmethans and partic- 
ularly into S3rmmetrical tetraphenyUethane (720). 

663. The method is suitable for transforming a secondary alcohol 
group into a ketone group even in mixed compounds. The secondary 
alcohol-ketones of the form R.CH(OH).CO.R' readily furnish the 
corresponding a-diketones.^® 

Under the same conditions, P^ydroxy-eatera can be transformed 
into keUm&'esters. Thus ethyl P^ydraxy-dsoheptoatSf (CH«)sCH.CHs.* 
CH(OH).CHtCOsC«Hs, is chuiged to ethyl P-keUHieoheptoaie.^^ 

Use of Other Metals 

664. Nickel. Reduced nickel acts more violently on the alcohols 
than does copper and the dehydrogenation of primary or secondary 
alcohols is always accompanied by a more or less considerable splitting 
up of the aldehyde or ketone, with the formation of carbon monoxide 
which may be more or less profoundly altered by the nickel ; a part 
being hydrogenated by the hydrogen formed from the alcohol and a 
part being changed to carbon and carbon dioxide (614). The sepa- 
ration of the carbon monoxide usually begins at the same time as the 
decomposition of the alcohol.^ 

Methyl alcohol is attacked as low as 180^, but two thirds of the lib- 
erated formaldehyde is destroyed. The reaction is rapid at 250^ but 
eight ninths of the aldehyde is destroyed and the gas evolved contains 
only 45% of hydrogen along with methane and carbon monoxide. 
At 350^ there is no longer any aldehyde and no carbon monoxide : the 
gas is a mixture of methane and carbon dioxide. 

Ethyl alcohol is decomposed from 150^ up, rapidly above 230^. 
As low as 180^, almost a third of the aldehyde formed \b decomposed, 
and at 330^ its destruction is complete. 

** Sabatibb and Mailhb, Atm. Ckim. Phjfs. (8), xo, 660, 664, 667 and 668 
(1907). 

•• QouMnoTH, SngUBh patent, 17,673 of 1906; /. 8. C. /., a6, 777 (1907).— 
Alot and Bbubtibb, BvU. Soc Ckim. (4), 9, 733 (1911). 

M BoTTYSAXTur and LocQunr, BvU. Soc. Ckim. (3), 35, 660 (1906). 

^ BoxnrBAXTur, Loc cit. 

* Babatobb and Ssnbbbbnb, Ann. Ckim. Phya. (8), 4, 469 (1906). 



666 CATALYSIS IN ORGANIC CHEMISTRY 238 

The results are similar with propyl alcohol, with which 75 % of the 
aldehyde is decomposed at 260^ ; and with nJmlyl alcohol with which 
92 % of the aldehyde is decomposed ; and for iaobutyl alcohol. With 
ordinary iaoamyl alcohol, the destruction of the aldehyde already 
reaches one half at 210°. 

Heptyl alcohol, submitted to the action of nickel at 220°, ^ves 
only a small amount of the aldehyde, the chief product being hexane 
resulting from its decomposition with separation of carbon monoxide.^ 

665. In contact with nickel, isopropyl alcohol is slowly decomposed 
into acetone and hydrogen from 150° up. The reaction is rapid at 
210° but about 12% of the alcohol that is transformed is spUt into 
water, ethane and methane. 

Secondary butyl alcohol is transformed quite regularly above 200° 
but 20 % of the product is already decomposed, while at 310°, 80 % is 
destroyed. 

For methyUhexyUcarbinol the decomposition is clean at 250° but at 
that temperature already the methyl-hexyl-ketone formed is mostly 
broken down into carbon monoxide, methane and hexane, only a third 
surviving. 

666. Cobalt. The action of reduced cobalt on primary and sec- 
ondary alcohols is between that of nickel and that of copper. ^^ 

667. Iron. The action of iron is analogous to that of cobalt. At 
high temperatures, 600 to 700°, it causes a rapid destruction. An iron 
tube either empty or filled with iron turnings decomposes ethyl alco- 
hol strongly at 700° giving 30 % aldehyde and depositing about 7 % of 
carbon.** 

668. Platinum. Platinum sponge acts on alcohols as does nickel 
but its action does not begin till above 250°. Besides the destruction 
of the aldehydes is inseparable from their formation and alwa3rs pre- 
dominates. 

Around 250° methyl alcohol is split cleanly into hydrogen and car- 
bon monoxide with no methane and only traces of formaldehyde. 

Eihyl alcohol is attacked at 270°, and at 370° the reaction is rapid, 
but 75% of the aldehyde is decomposed into carbon monoxide and 
methane. 

Propyl alcohol is split above 280°, but at 310° the aldehyde is 
almost completely decomposed into ethane and carbon monoxide. 

The results are better with secondary alcohols since the ketones 
are more stable than the aldehydes. 

* BoESBiODN and Van Sbndbn, Bee. Trao. Chim. Paye-Bae, 3a, 23 (1913). 
^ Sabatibb and Sbndbbbns, Ann. Chim. Phye. (8), 4, 473 (1005). 
« Ipatibf, BerichU, 35, 1047 (1902). 



239 DEHYDROGENATION 678 

Isopropyl alcohol is transformed into acetone at 320^ without 
notable complications and at 400^ the destruction of the acetone 
reaches barely 3 % of the product.^' 

669. Palladium. The considerable affinity that this metal has for 
hydrogen seems to fit it for the dehydrogenation of alcohols. Bern- 
hydrol is rapidly decomposed into benzophenone by contact with 
paUadium eponge.^ 

670. Zinc. Around 650° this metal decomposes alcohols strongly : 
eihyl alcohol yields 60% aldehyde and the gases, ethylenCi carbon 
monoxide and methane. laobutyl alcohol gives 75 % of aldehyde and 

, gas which is largely butylene. 

Braes, an alloy of copper and zinc, acts at 600° like zinc.^^ 



Use of Other Materials 

671. The use of other substances to dehydrogenate alcohols is not 
advantageous since they act much less energetically than the metals 
and because they require the use of higher temperatures at which the 
aldehydes are decomposed into carbon monoxide and saturated 
hydrocarbons. 

672. Manganous Oxide. Its action hardly begins below 320°. At 
360° it decomposes methyl alcohol only one sixth as rapidly as compact 
red-orange copper; the greater part of the formaldehyde survives and 
the hydrogen is nearly pure. 

At 360° the decomposition of ethyl alcohol is only one fortieth as 
rapid as with light copper and a part of the aldehyde is already de- 
composed into ethane, carbon monoxide and even carbon dioxide, the 
latter being formed from the carbon monoxide with a corresponding 
deposit of carbon, the reaction being similar to that produced by 
metals (614). 

Propyl, ieoamyl and benzyl alcohols give analogous results.^* 

673. Stannous Oxide. This acts above 300° as a dehydrogenation 
catalyst after the manner of the metals, but is slowly reduced mean- 
while into metallic tin, which is easy to see in the oxide. This finely 
divided tin seems to possess a catal3rtic power similar to that of the 
oxide so that the mixture of metal and oxide continues to split alco- 
hols into aldehydes and hydrogen for a long time, but as the reaction 
temperature is above 220°, the melting point of tin, the tiny globules 

** Sabatdbr and Sundbbbns, Ann, CMm, Phys, (8), 4» 473 (1905). 
«^ Enobvbnagxl and Hxcksl, Berichte, 361 2816 (1903). 
«• Ipatzbf, Berichte, 34, 3579 (1901) and 37f 2961 and 2986 (1904). 
^ Sabatisb and Mazlbx, Ann, Ckm. Phye. (8), ao, 313 (1910). 



674 CATALYSIS IN ORGANIC CHEMISTRY 240 

of metal resulting from the reduction of the oxide gradually coalesce 
into larger, and consequently the activity diminishes. 

Thus with ethyl alcohol^ the brownish orange stannous oxide (re- 
sulting from the reduction of stannic oxide by the alcohol vapors) 
conunences to act at 260^. At 350^ the velocity of the reaction is 
almost half as great as with the same volume of very light reduced 
capper. The disengaged hydrogen is almost pure, the acetaldehyde 
being only slightly decomposed. At the end of four hours the velocity 
of the reaction is reduced by half. 

Amyl alcohol 3delds the aldehyde regularly at 340^ 
Methyl alcohol is attacked above 260^ with the production of form- 
aldehyde. At 350^ the most of this is decomposed into carbon mon- 
oxide and hydrogen.^ 

674. Cadmium Oxide. This behaves like stannous oxide and de- 
hydrogenates while it is reduced at the same time to the metal which 
possesses a catalytic activity differing little from that of the oxide. 
Thus with ethyl alcohol at 300^ the reaction is about one tenth as 
rapid as with the same volume of very active copper and maintains 
itself for a long time in spite of the progressive reduction of the oxide. 

Benzyl alcohol acts in exactly the same way : at 350^ there is a 
slow reduction of the oxide and at the same time a splitting of the 
alcohol into benzaldehyde and hydrogen. At 380^ the benzaldehyde is 
partially decomposed into benzene and carbon monoxide. The entire 
absence of the resinous hydrocarbon (714) indicates that there is no 
dehydration. 

With methyl alcohol, the splitting which begins at 250^ is quite 
rapid above 300^ and produces formaldehyde which is partially de- 
composed into carbon monoxide and hydrogen.*^ 

675. Other Oxides. Most non-reducible metallic oxides are mixed 
caialyete for alcohol, causing dehydration and dehydrogenation at 
the same time. For some : uranous oxide, blue oxide of molybdenum, 
vanadous oxide, VsOs, zinc oxide, dehydrogenation predominates. 

In another group : beryllium oxide, zirconium oxide, chromic 
oxide, CrsOi (calcined above 500^), the dehydrogenating and dehy- 
drating powers are about equal. 

For a third group : chromic oxide, CrsOi (not calcined), titanium 
oxide, silicon dioxide, dehydration predominates. 
I 676. With reference to methyl alcohol the classification of the 

oxides is quite different since in this case dehydration can not take 
place except by the formation of methyl ether and the conditions are 

^ Sabatobb and Maujob, Ann, Chim. Phye, (8), ao, 309 (1010). 
^ Sabatibb and Mailhb, Ann, Chim, Phye. (8), 20, 302 (1010). 



241 DEHYDROGENATION 878 

not comparable. Except alumina, which at 390^ only dehydrates, 
and several oxides (thoria, blue oxide of tungsten, chromic oxide and 
alumina above 350^) which are mixed catalysts, all metallic oxides 
dehydrogenate methyl alcohol with the production of formaldehyde 
which is more or less decomposed into carbon monoxide and metlume. 
The following table indicates the volmne of gas obtained per min- 
ute with the oame volume of various catalysts employed imder the 
same conditions. 

Oxides Volume of gas in cc. per minute. 

Fonnaldehyde remaining almoiC eniirdy; ike gae ie neady jnan hydrogen, 

BeO very small 

SiOj 0.3 

TiOj 1.2 

ZnO 1.6 

ZrO» 1.8 

MnO 2.0 

AUO, 6.0 

FcrmaUkhyde partially decomposed, the hydrogen eoniains carbon monoxide, 

PbO". 45 (beginning) 

MoiO, 64 

CdO 67 (beginning) 

Formaldehyde almost completely destroyed, the gas is nearly CO + 2H|. 

FetO,« 106 (beginning) 

ViDi 140 

SnO« 160 (beginning) 

light copper 152 

677. The dehydrogenating power of oxides can hardly be explained 
except by assuming an unstable combination of the oxide and the 
aldehyde.** 

678. Zinc powder, which is an intimate finely divided mixture of 
metallic sine and sine oxide, usually containing a certain proportion 
of cadmimn and cadmium oxide, acts by virtue of these various 
substances as a quite active dehydrogenation catalyst, particularly 
toward methyl alcohol, the formaldehyde being mostly decomposed 
into carbon monoxide and hydrogen. Long ago Jahn noted that zinc 
powder splits methyl alcohol into a gas containing 30% carbon 
monoxide and 70 % hydrogen.^ 

* The gas volumes given are taken after the absorption of the caibon dioxide 
resulting from the dow reduction of the oxide. 

" Babatibb and Mazlbx, Ann. Ckim. Pkys. (8), 20, 340 to 346 (1010). 
M Jahn, BerichU, xa» 983 (1880). 



679 CATALYSIS IN ORGANIC CHEMISTRY 242 

679. Carbon. Baker's coals act towards alcohols as a mixed cata- 
lyst causing dehydrogenation and dehydration simultaneously. 

Ethyl alcohol undergoes a complex reaction at 375-^385% being 
almost completely destrojred yielding methane and carbon monoxide. 
With isopropyl alcohol dehydration predominates.** 

fi 4- — DBHYDROGBNATION OF POLY-ALCOHOLS 

680. Glycerine is the only poly-alcohol of which the dehydrogena^ 
tion has been studied. When its vapors are passed at 330^ over very 
light reduced copper^ prepared by the reduction of cupric carbonate at 
a low temperature, there is a rapid evolution of gas consisting of hy- 
drogen mixed with methane, carbon monoxide and dioxide, the pro- 
portion of the latter rising to one third of the whole. 

The initial effect of the copper is dehydrogenation to glyceric 
aldehyde: 

CH,OH.CHOH.CH,OH - H, + CH,OH . CHOH . CHO. 

As soon as this is formed it is decomposed in the same way as it 
is by beer yeast into ethyl alcohol and carbon dioxide: *' 

CHjOH. CHOH. CHO - COj + CH,.CH,OH. 

A part of this alcohol is found in the distillate and a part suffers 
dehydrogenation by the copper to acetaldehydOf CHs.CHO, which 
itself splits up, more completely when the temperature is high, into 
methane and carbon monoxide. 

Furthermore, at the temperature of the reaction a portion of the 
glycerine is dehydrated to acrolelnef which is mostly found in the dis- 
tillate with the alcohol and water but a part of which is hydrogenated 
by the copper to propionic aldehyde, allyl alcohol and propyl alcohol 
accompanied by condensation products due to the crotonization of the 
aldehydes. Ethyl alcohol is the chief constituent of the liquid.*' 

§ 5* — DEHYDROGENATION OF AMINES 

681. Primary Amines. We have seen that nickel permits us to add 
hydrogen to nitriles at 200° to form primary amines (426). We may 
expect that it will reverse this reaction at higher temperatures and take 
hydrogen away from a primary amine derived from a primary alcohol, 
to reform the nitrile: 

R.CHj.NHj - 2Hj + R.CN. 

" LmfomB, BulL Soc. Ckim. (4), 3, 851 and 935 (1908). 

M Qbdiaux, BvU. Soc Ckim. (2), 49, 251 (1888). 

" Babatdbb and Gaudion, CompL rend,, x66| 1037 (1918). 



243 DEHYDROGENATION 688 

This is what takes plaoe with benzyUamine, with amylramine as 
well as with other primary aliphatic amines derived from primary 
alcohols having at least five carbon atoms. ^^ 

When the vapors of benzylramine alone are passed over a layer of 
reduced nickel maintained at 300-50°, benzonitrUe, CeHs.CN, is 
formed. But at this temperature the Uberated hydrogen reacts with 
the amine to give toluene and ammonia (496), so that the evolution 
of gas is a minimum. We may write the reaction: 

3C«H6.CH,.NH, - CaHj.CN + 2C.H5.CH3 + 2NH,. 

The yield of benzonitrile is about one third. 
Likewise at 300° isoamylramine yields isobutyl cyanide according to 
the reaction: 

3(CH,),CH.CH,.CH,.NH, - (CH,)2CH.CH,.CN + 2C.H12 + 2NHi. 

The isopeniane produced is partially destroyed by the nickel, de- 
positing carbon and liberating hydrogen and lower hydrocarbons. 

The reaction goes poorly with amines derived from primary alco- 
hols having less than five carbon atoms, since with these amines nickel 
has a strong tendency to eliminate ammonia with the formation of 
ethylenic hydrocarbons (631).** 

When copper is used in place of nickel between 390 and 400°, 
much more complex products are obtained somewhat similar to those 
obtained by the hydrogenation of aliphatic nitro compoimds (510). 

682. Secondaiy and Tertiaiy Amines. Secondary and tertiary 
amines derived from primary alcohols also furnish nitrUea when 
passed over nickel at 320-50°, by the simultaneous elimination of 
hydrogen and ethylenic hydrocarbons. Thus from di4soainyUainine 
and tririsoarnyl-amiTiej isobutyl cyanide is obtained.*^ 



§ 6. — SYNTHESIS OF AMINES 

683. When a mixture of ammonia and benzene vapor is heated to 
550° without catalyst, a slight formation of aniline is observed 
according to the reaction : *^ 

C«H« + NH, - H, + CA.NH,. 

M Sabahbb and Gaudion, CompL rend., 265, 224 (1917). 
** Sabatdbb and Gaudion, Compt. rend,, 265, 310 (1917). 
M MAUiEB and dh Gtodon, Compt. rend,, z65i 557 (1917). — Mailhs, Ibid., z66, 
996 (1918). 

tt MsTBB and Tauzbn, Beriehte, 469 3183 (1913). 



684 CATALYSIS IN ORGANIC CHEMISTRY 244 

With hydrogen in presence of nickel above 350% aniline vapors 
regenerate a certain amount of benzene and ammonia by the reversal 
of the above reaction (496)." 

It might be hoped that the direct production of aniline from ben- 
zene vapor and ammonia would be feasible by the use of metal cata- 
I3r8t8 at 500 to 700^ It has been found that the presence of reduced 
nickelf iron or capper is of no advantage, as only traces of aniline 
are produced. Likewise only traces of iduidine are obtained from 
toluene. In the most favorable case working with nickeled asbestos in 
an iron tube, 0.11 g. aniline was obtained from 200 g. benzene.** 



§ 7- — CLOSING OF RINGS BY LOSS OF HYDROGEN 

684. Nickel. Methyl^.toluidinef submitted to the action of re- 
duced nickel at 300-30^ (in presence of hydrogen), loses hydrogen to 
form a new cyde, yielding above 6 % of indol along with methane and 
oMuidine: ^ 

/CH« /^^\ 

^NNH.CH. ^NNH/ 

Likewise dimethyl^.toluidins, at 300^, yields 24% of N-methyl- 
indol along with methane, toluidine and methyl-toluidine: ** 

\N(CH,), ^N.CH, 

685. Aluminum Chloride. The use of anhydrous aluminum chlo^ 
ride at moderate temperatures, between 80 and 140^, causes the elim- 
ination of hydrogen with the formation of new cycles. 

a-Dinaphthyl yields perylene: ** 





Likewise at 140^, mseo-benzoHiianihrone passes quantitatively into 
meeo^naphtho^ianthrone: ^ 

** Sabatubb and Sbndbbsnb, Aha. Ckim. PKye. (8), 4, 415 (1905). 

« WiBAUT, BeridUe, 50, 041 (1917). 

^ Cabbasco and Padoa, Lincei^ 25 (2), 699 (1906). 

• Cabbasco and Padoa, Ou. CUm, Ital., 37 (2), 49 (1907). 

** Scroll, Sbxb, and WmunBNBOCK, BeriehU^ 43, 2203 (1910). 

*' ScHOLL and Mambixbld, BerickUf 43, 1787 (1910). 



245 DEHYDROGENATION 686 





At 140^ phenylra-^naphthylrlceUme gives a good yield of benzanthrons: 





This is a typical example of many analogous reactions that can be 
readily carried out by this process.** 

686. Metallic Oxides. Various anhydrous metallic oxidesi alu- 
mina, ferric oxide, chramium irioxide, thoria, and tUania can cause 
the condensation of acetylene with various molecules with the elim<- 
ination of hydrogen and the formation of cyclic compounds. 

Tf^th ammonia pyrrol, picoline and collidines are formed, there 
being no hydrogen evolved in the formation of the latter: 

2C,H, + NH, - H, + CJgtN 

pyiTol 

SCtHi + NHt - Hi + C«HrN 



4C>H, + NH» - C>HuN 

Ferric oxide is the best catalyst for forming pyrrol. 

When eUiylens is used instead of acetylene, the same products are 
formed but at higher temperatures and with the evolution of much 
hydrogen. 

Hydrogen sulphide gives tkiophene: 

2CiHs + HsS - Hs + C4H43. 

At 400-425% water vapor forms furfural: ** 

2CsHs + HaO - Hs + C4H4O. 

M ScHOix and Sma, SU». Akad. Wien, lao, 11, B, 925 (1911). — Annalbn, 

394. Ill (1912). 

« CmcBniABiNB, /. Ruaeian Phy$. Chem. Soe., 47, 703 (1915), C. A., g, 2612 
1915). 



CHAPTER XV 

DEHYDRATION 

687. Thebb are a large number of organic reactions which take 
place with the elimination of water. Many of them can be started or 
accelerated by the presence of so-called dehydration catalysts. As 
might be anticipated from the great variety of reactions of this kind, 
dehydration catalysts comprise many substances of very different 
natures, elements (phosphorus, carbon, and finely divided metals), 
strong mineral acids (sulphuric, hydrochloric, phosphoric, etc.), either 
concentrated or dilute, anhydrides of acids (phosphoric and boric), 
anhydrous chlorides (of aluminum, sine and iron), various inorganic 
salts (ammonium salts, potassium bisulphate, calciimi and aluminum 
sulphates, i^osphates, etc.), organic acids (acetic), as well as their 
salts (potassium and sodimn acetates). 

We can distinguish two distinct modes of dehydration according 
to whether it takes place in the gas phase by the action of solid cata- 
lysts on the vapors which are to give up the water or in the liquid 
medium. We will study the two separately. 

SI. — DEHYDRATION OF ALCOHOLS ALONE 

688. Priman^ alcohols can undergo dehydration in two different 
ways : to produce an ether or a hydrocalrbon, usually unsaturated. 
Thus with ordinary alcohol, we have : 

2CH,.CH20H - H2O + (CH,.CH»)20 

ethyl ether 

and CHs.CHjOH = H2O + CH2 : CH2. 

ethylene 

Benzyl alcohol gives : 

2C«Hi.CH20H - H2O + (C>Hb.CH2)20 

beniyl ether 

or nCACHiOH - nH^ + (C«Ht.CH)„ 



rednous hydrocarbon 

Methyl alcohol is an exception, as it can be dehydrated regularly 
in only one way, that is to form methyl ether, (CH«)20. 

Secondary alcohols, the dehydration of which is easier, yield ethers 
in exceptional cases only (e.g. benzhydrol), usually producing hydro- 
carbons. 

246 



247 DEHYDRATION 691 

The ethers can seldom be obtained from tertiary alcoholSf as these 
are dehydrated to the hydrocarbons with still greater ease. 

689. These dehydrations can be accomplished by a multitude of 
substances, that have aflSnity for water, used in excess compared 
with the alcohol that is to be dehydrated. But if the hydrates 
formed are unstable at the temperature of the operation, water is 
given off, regenerating the original substance which can repeat the 
reaction with a fresh quantity of alcohol. 

This is what takes place with zinc chloride and with concentrated 
sulphuric acid of which a small quantity when heated can dehydrate 
a large amount of alcohol. 

We have explained above (159) the mechanism of the action of 
sulphuric add which produces either ethyl ether or ethylene from alco- 
hol according to temperature conditions. It can continue its cata- 
lytic r61e for a long time, but is gradually diminished by being reduced 
to sulphur dioxide, since it slowly oxidises the alcohol with the pro- 
duction of carbon dioxide and of tarry matters. 

Syrupy phosphoric add can produce an entirely analogous effecti 
and, as it is less readily reduced than sulphuric acid, can maintain its 
catalytic activity for a much longer timei.*' * 

Formation of Ethers 

690. The formation of ethers by the direct dehydration of alcohols 
is possible in only a small number of cases and only with primary 
alcohols. 

In the case of methyl alcohol this is the only possible manner of 
dehydration and a considerable number of catalysts can decompose its 
vapors into methyl ether and water, but they are very much less 
niunerous than the substances which can dehydrate other alcohols to 
hydrocarbons. 

691. Formation in Liquid Medium. Concentrated sulphuric add 
is usually employed to dehydrate methyl alcohol to methyl ether,^ 

Zinc chloride is not suitable for this reaction as it gives gaseous 
products by a complicated reaction and even produces a certain 
amount of hexamethyJrbenzene.^ 

Ethyl ether is practically prepared by the action of sulphuric add 
at 140*. A mixture of 5 parts of 90% ethyl alco?u>l and 9 parts of 

1 Sabatubb and Mah^he, BuU, Soc. Chim, (4), 1, 524, (1907). 
' This is used for preparing ethylene on a commercial scale. — E. £. R. 
< Dumas and PAugot, Ann, Chim, Pkys. (2), 08, 19 (1835). 
« Lb Bbl and Grsbnv, Compt. rend,, 87, 260 (1878). — Jakresher. Chem., 1878, 
388. 



692 CATALYSIS IN ORGANIC CHEMISTRY 248 

concentrated sulphuric acid is used. This mixture boils at about 140*. 
When it is heated to 140*, ether distils over and alcohol is added at 
such a rate that the boiling point does not rise. A large amount of 
alcohol can be transformed into etAer in this way. The volume of the 
ether may be more than 167 times that of the sulphuric acid used.^ 
Theoretically the formation should continue indefinitely, but the yield 
decreases after a certain time on account of the production of a car- 
bonaceous residue which may amount to 6% of the acid and the for- 
mation of which corresponds to the evolution of a considerable amount 
of sulphur dioxide. 

The best yield of ether is obtained between 140 and 146*, as above 
that temperature more and more ethylene is formed.* 

Phosphoric or arsenic add may replace the sulphuric acid in this 
preparation.^ Anhydrous zinc chloride also may be used." 

Concentrated sulphuric acid at 135* produces propyl ether from the 
alcohol but the yield is poor because much propylene is formed. 

The higher alcohols such as isobutyl do not yield ethers with con- 
centrated sulphuric acid but only the ethylenic hydrocarbons.^ Never- 
theless, isoamyl ether can be thus obtained (696). 

Sometimes sulphuric acid at 140* enables us to obtain mixed ethers 
by operating on a mixture of the two alcohols. This is the case with 
methyl and ethyl alcohols which yield the mixed methyl-ethyl ether 
along with the two simple ethers. In the same way eihyUpropyl ether 
may be obtained, but elhyUisobutyl can not be. EthyUisoamyl ether, 
which several chemists have failed to obtain, ^^ can be prepared along 
with the two simple ethers by the action of 85% sulphuric acid at 
136-140*." 

The mixed ethyUiertiary-iutyl ether can be obtained by heating 50 
volumes of a mixture of two molecules of ethyl alcohol and one of 
trimethylrcarbinol with one volume of sulphuric acid in a sealed tube 
at 100* for 6 hours." 

692. Although it is a secondary alcohol, benxhydrol, C6Hft.CH(0H).- 
CeHft, is readily transformed into its ether: it is sufficient to heat it 
to 180* with 27% sulphuric acid." 

* Evans and Sutton, Jour, Avwr, Chem, Soc., 86, 794 (1913). 

* NoBTON and Pbbscott, Amer, Chem. Jowr,, 6, 243 (1834). 
' BouLAT, GQberV9 Annate, 44, 270 (1913). 

* Masbon, ilnnoZen, 81, 88, (1839). 

* NoBTON and Pbbscott, Avwr, Chem. Jour., 6, 244 (1884). 

l^ GuTHBOB, AnnaUn, 106, 37 (1858). — Nobton and Pbbscott, Amer. Chem. 
Jour., 6, 246 (1884). 

" Petbb, BerichU, 88, 1419 (1899). 

u Mamontofp, /. Ru89ian Phy%. C em. Soc., 29, 234 (1897), C, 1897 (2), 408. 

^ ZAGinoBNNi, /. Ruman Phy. Ckm. See., 18, 431 (1880), C, 1880, 029. 



249 DEHYDRATION 696 

The ether may be obtained also by heating benzhydrol to 210- 
220® with finely divided copper. ^^ 

693. Formation in Gaseous Phase. Among anhydrous metallic 
oxides, only alumina precipitated and dried at a low temperature 
effects the transformation of methyl alcohol into methyl ether 
exclusively. The reaction commences at about 250® and is rapid at 
300®, yielding methyl ether which can be completely absorbed by 
concentrated sulphuric acid. At about 350® the dehydration is accom- 
panied by a sUght dehydrogenation, the aldehyde produced being 
immediately decomposed into carbon monoxide and hydrogen. 

Thoria, blue oxide of tungsten and chromium eeequioxide can dehy- 
drate methyl alcohol to the ether above 230® but there is simultaneous 
dehydrogenation to the aldehyde and its decomposition products. 
The latter reaction is still more important with tUania and tfiJces place 
almost exclusively with other catalytic oxides, such as the oxides of 
zirconium J molybdenum, and vanadium.^^ 

694. Alone among the oxides, alumina at 240® enables us to obtain 
^yl ether from ethyl alcohol. A httle ethylene is evolved. A 90% 
alcohol may be used. 

With propyl alcohol at 250® it gives a little propyl ether but forms 
propylene chiefly. It can not produce the other ethers.^* In the 
apparatus of Ipatief , under high pressures, alumina can transform 
eihyl alcohol into the ether , but the formation is limited by the reverse 
reaction. At higher temperatures only ethylene is produced. ^^ 

Ethyl ether is totally decomposed into water and ethylene by 
alumina at 380®.^^ 

Dehydration to Hydrocarbons 

695. The dehydration of a single molecule to give a hydrocarbon 
with an ethylene double bond is the normal reaction of alcohols and 
also of ethers. 

Reaction in Liquid Medium. This may readily be accomplished 
by concentrated non-volatile mineral adds and also by anhydrous 
zinc chloride. 

696. Concentrated Mineral Adds. A small proportion of con- 
centrated sulphuric add used at a temperature high enough to eliminate 
the water produced serves to prepare advantageously the lower eth- 
ylenic hydrocarbons which are gases, ethylene, propylene, and butylene. 

^^ Knoxvenagel and Hxckxl, Berichte, 36, 2823 (1003). 

" Babatcdb and Maxlhb, Ann. Ckim. Phys. (S), ao, 345 (1910). 

^* Sbndebemb, Ann. CHm. Pkys. (8), 25, 440 (1012). 

^' Ipatief, BerichU, 37, 2961 (1004). 

^* Engeldbb, /. Phys. Chem., 21, 676 (1917). 



687 CATALYSIS IN ORGANIC CHEMISTRY 250 

To obtain ethylene, a mixture of 25 parts of alcohol and 150 parts 
of sulphuric acid is heated to 160-70° and a mixture of alcohol and 
sulphuric acid is added in drops. ^* 

The evolution of gas is facilitated by the addition of a certain 
amount of fine quartz sand to the mixtiu'e. According to Senderens, 
this acts as a true chemical catalyst. According to the same author 
the results are still better when 5 % of anhydrous aluminum sulphate 
is added to the usual mixture of alcohol and sulphuric add. With 
ethyl alcohol at 157° the evolution of ethylene is thus rendered three 
times as rapid and propylene is formed at 130° instead of 145°; iso- 
butyl alcohol is spUt at 125°.«« " 

From 1500 cc. isoamyl alcohol and 100 cc. sulphuric acid in a 
vessel provided with a reflux condenser kept at 60-90° followed by a 
condenser for the amylene, 250 g. of amylene (a mixture of the 3 
isomers) may be prepared in 8 hours. The alcohol remaining in the 
flask contains 400 g. isoamyl ether." 

Concentrated phosphoric add may replace sulphuric acid in these 
dehydrations. 

697. Under analogous conditions the dehydration of molecules 
with mixed function may be catalyzed. Thus diacetonyl alcohol, 
(CH«)tC(0H).CH2.C0.CHj, warmed with traces of sulphuric acid 
(6 drops to 290 g. of the alcohol), furnishes mesityl oxide, (CHOaC : 
CH.CO.CH,, with a high yield (190 g.) on distillation." 

698. Zinc Chloride. Anhydrous fused zinc chloride is very often 
employed to effect the transformation of alcohols into ethylene hydro- 
carbons, but it is commonly used in excess, that is in amoimt more 
than sufficient to fix as a stable hydrate all of the water that is 
eliminated. The same action can be exercised by the catalyst when 
the alcohol has a high boiling point as the alcohols of the cydohexane 
series; a small quantity of the chloride serves to dehydrate these to 
cyclohexenes since the water that is extracted is eliminated by dis- 
tillation along with the hydrocarbon so that the catalyst is continu- 
ously regenerated. 

699. Iodine. In exceptional cases, iodine serves to effect the regu- 

^* Erlbnmbtsb, Annalen, 192, 244 (1878). 

'0 SsNDBRENB, Compt. fend,, i$i, 392 (1910). 

*^ Following the observations of Sendebenb, the following method of preparing 
ethylene has been devised and has given excellent service. In a 500 cc. flask 200 
c.c. cone, sulphuric acid, 100 cc. 95 % alcohol and 25 g. of dehydrated alum are 
heated to 157 to 175^, the thermometer dipping in the mixtiire. One operator 
repeated this five times in an afternoon and obtained 667 g. ethylene bromide. 
'-*~ £. £. R. 

** Adams, Kaicm, and Marvel, Jaw. Amer. Chem, Soe., 40, 1050 (1918). 

s* KoBN, Monaish, Chem., 34, 7T9 (1913). 



261 DEHYDRATION 702 

lar dehydration of compounds containmg alcohol groups. DiaceUmyl 
alcohol, (CHs)aC(OH).CHs.CO.CH«, which distillation alone breaks 
down partially into two molecules of acetone, is dehydrated by sul- 
phuric acid to mesityl oxide (697). The same dehydration takes place 
quantitatively when it is distilled with a small amoimt of iodine.*^ 

700. Reaction in Gaseous System. This can be effected by a 
large nimiber of solid catalysts among which the best are aluminaf 
day, thoria and the blue oxide of tungsten. 

Elements. Animal charcoalf extracted with hydrochloric acid, is a 
rather mediocre catalyst for alcohols : above 350^ it produces ethylene 
from ethyl alcohol, accompanied by a certain amount of methane, car- 
bon monoxide and hydrogen resulting from the formation of acetal- 
dehyde which is mostly destroyed. Propyl alcohol, above 300^, gives 
a gas of which 87% is propylene, with ethylene and other gaseous 
products.** 

Red phoephofue acts more rapidly at much lower temperatures and 
probably owes this activity to small amounts of phosphorus and 
phosphoric acids preSxistent in the material and which are formed in 
considerable amounts in consequence of the oxidation of the phos- 
phorus by the alcohol with a correlative production of phosphine. 

With ethyl alcohol at 240^, a rapid evolution of ethylene is obtained 
containing 5% phosphine. Similar results are obtained with propyl 
alcohol. The proportion of phosphine is less with normal and ieo^yuiyl 
alcohols and negligible with isopropyl alcohol which is already split at 
160^ 

The presence of phosphine, which is difficult to get rid of, takes 
away much of the interest in this case of catalysis. 

701. Finely divided metals have an important catalytic dehydro- 
genating effect on primary and secondary alcohols (651); but they 
decompose tertiary alcohols rapidly at moderate temperatures into 
unsaturated hydrocarbons. Reduced nickel acts in this way without 
complications at 220 to 300^ and reduced copper acts similarly above 
280 to 300^" 

Passing an aliphatic alcohol over copper at 300^ is a simple method 
of determining its class. A primary alcohol forms an aJdehyde, a 
secondary one a ketone, while a tertiary breaks up into water and an 
imsaturated hydrocarbon.^ 

702. Anhydrous Metal Oxides. Grigoreff in 1901 was the first to 
note the special aptitude of an oxide to dehydrate alcohols : he found 

** HiBBBBT, Jour. Amer. Chem. Soc., 37, 1748 (1915). 

** Sendebemb^ Compt, rend,, 144, 381 (1907). 

'* Sabatisb and SemdebbnBi Ann, Chim, Phys, (8), 4, 467 and 472 (1905). 

" Sabatixb and Sxmdbbbmb/ BuU. 8oe. Chim. (3), 33, 263 (1905). 



702 



CATALYSIS IN ORGANIC CHEMISTRY 



252 



that oZumtno decomposes ethyl and propyl alcohols to the hydrocar- 
bons with 90% yields.** 

This property of oZumtna was studied by Ipatief and found also in 
the material of graphite crucibles, which is a mixture of graphite 
(inactive) and day, while other oxides (of sine, iron, tin, chromium, 
etc.) were revealed as dehydrogenating catalysts.** 

The catalytic activity of various oxides was made the object of a 
thcnrough study by Sabatier and Mailhe,** who were able to demon- 
strate the great dehydrating power of Owria and of the Hue oxide of 
ivMQtimi, We have abeady noted (675) that the oxides that are not 
reducible, or only slowly reducible, by alcohols can be divided into 
dehydrogenoHng, dehydrating, and mixed catalysts which cause both 
reactions simultaneously. 

The direction and the importance of the activity of the various 
oxides can be clearly shown by a comparison of the volume and com- 
position of the gas evolved by them, when equal volumes of them are 
used at Z^O-W with the same amount of ethyl alcohol; all of the 
oxides having been prepared below 350°:*^ 



Dehydrating 



Mixed 



Oxide 




Volume of 
gas in cc. per min. 

... 31 
... 21 
... 67 



Cr,0, 

SiOf 

TiO, 



4.2 
0.9 
7.0 



< 



BeO 
ZrOt 



1.0 
1.0 



UO, . 
MojOi 
FeiOt 
V,0, . 
IZnO . 



14 

5 

32 

14 

6 



Dehydrogenating | 



MnO 3.5 

MgO traces 



Gompoaitioii 
CiH4% H,% 

100 trace 

98.5 1.5 

98.5 1.5 



91 
84 
63 



45 
45 



24 

23 

14 

9 

5 








9 
16 
37 



55 
55 



76 
77 
86 
91 
95 



100 
100 



** GuooBarr, /. Rtutian Phy$. Chem. Soc, 33, 173 (1901). 

*• IPATixr, BeriehU, 34, 696 (1901); 35, 1047 (1902); 36, 1990 (1903). 

M Sabatixb and Mailhb, BvU. See. Ckim. (4), i, 107, 341, 524 and 733 (1907). 
— Compt. rmd., 146, 1376 (1908); 147, 16 and 106 (1908); 148, 1734 (1909).— 
Arm, Ckim, Phy. (8), ao, 289 (1910). 

u SABATimt and Maohi, Ann. Chkn. Pky. (8), ao, 341 (1910). 



253 DEHYDRATION 707 

703. We have noted (76) that the physical eonditian and the 
method of preparation of an oxide have a great influence on its ac- 
tivity and even on the direction of the catalysis. 

These differences are very marked for the various varieties of 
chromium sesquioxide (78) the only one of which that is suitable for 
the dehydration of alcohols is that obtained by drying the precipitated 
blue hydrated hydroxide below 350^. 

704. Titanium oxidei TiOs, prepared by calcining at a red heat 
has very httle activity. To obtain a suitable oxide, the hydroxide 
prepared by the action of ammonia on titanium chloride is dehydrated 
below 360°.« 

705. Ctjrstallized silica is almost without action on alcohols 
below 400^. The pure silica obtained by decomposing silicon 
fluoride by water, washing thoroughly and drying at 300^, is also 
only slightly active. The most active form is obtained by adding 
dilute Stcid to sodium sUicatef washing and drying the gelatinous 
precipitate. 

706. The most active form of alumina is prepared by precipita- 
tion from aluminum nitrate, washing the precipitate well and drying 
at 300^. Good results are also obtained with the oxide prepared by 
calcining pure ammonium alum at red heat. The basic aluminum 
sulphate obtained by calcining aluminum sulphate at a dull red is a 
very active catal3n3t. On the contrary, preparations of alumina which 
have been heated to redness for a long time are almost inactive and 
sometimes do not give an appreciable amount of gas from ethyl 
alcohol even at 420^•• 

BauxitSf aluminum hydroxide mingled with silica and ferric hy- 
droxide, has low catalytic power and dehydrogenates chiefly at about 
400^»* 

The nature of the reaction catalyzed is closely connected with the 
condition of the oxide and bears a certain relation to its ease of 
solution in acids.'* 

707. Thoriai on the contrary, does not present these difficulties 
and its catalytic activity is not sensibly diminished by calcination at 

** Sabatddb and Mailbm, Ann, CMm. Phys, (8), ao, 326 (1910). 

" Sabatibb and Mailhb, Ann, Chim, Phy$. (8), ao, 300 (1910). 

"* Samples of bauxite from different sources differ widely in catalytic power. 
With iBoamyl alcohol a sample of German bauxite gave gaseous products but poor 
yields of amylene, while a Tenneesee sample gave little gaa and an excellent yield 
of amylene. The bauxite was used in a copper tube 35 x 900 mm. at about 400% 
the alcohol being admitted at about 100 drops per minute. Several pounds of 
amylene were thus prepared. — C. H. Milligan. 

» IPATiBF, BeriehU, 37, 2986 (1904). 



708 CATALYSIS IN ORGANIC CHEMISTRY 254 

red heat : it seems that its high molecular weight may be in the way 
of molecular condensations such as alumina appears to undergo when 
heated to redness.** 

708. There are great differences in the duration of the catal3rtic 
activity of various oxides; usually it goes on decreasing because the 
surface of the oxide is gradually covered by small amounts of tarry or 
carbonaceous matter which hinder gaseous exchanges and also because 
molecular condensations take place in the oxides, without doubt, even 
when the temperature of the reaction is below 400°. If we consider 
only the three good dehydration catal3rsts, alumina, thoria, and the 
blue oxide of tungsten, alumina, the lightest molecule (AI2OS, molec- 
ular weight 92) is the one which weakens most rapidly. An active 
specimen which disengaged 14 cc. ethylene per minute at 340°, gave 
only 7 cc. after three hours of use.*' 

However certain observers have found no weakening after five 
hours.** *• 

The blue oxide of tungsten is much more permanent : the evolution 
of gas may continue for several hours without noticeable weakening. 
The same is true of thoria which has the great additional advantage 
of being very readily regenerated when long usage has gummed it up; 
calcining at a red heat for a few instants is sufficient to render it 
perfectly white and restore its original activity.*® 

709. For a given catalyst, elevating the temperaiure greatly accel- 
erates the reaction. By operating under the same conditions with 
ethyl alcohol and the blue oxide of tungsten, it has been found 
that the evolution of ethylene begins at about 250° and becomes 
more and more rapid as the temperature rises. The yield per 
minute was : 



** In the catal3rtic preparation of mercaptans, Krambb and Rsm (J. Amer, 
Chem, Soc. 43, 882 (1921)) find that the activity of a thoria catalyst depends some- 
what on the temperature to which it has been subjected, being considerably di- 
minished by heating much above 400^. Some preparations of thoria such as Wels- 
bach gas mantles and the extremely voluminous product obtained by dropping 
thorium nitrate into a red hot crucible are absolutely inactive so far as this reaction 
is concerned. — £. £. R. 

*' Sabatdcb and Mailhe, Ann. Chim, Phya, (8), ao, 299 (1910). 

»• Engbldbr, /. Phya. Chem., ai, 676 (1917). 

'* I have used the same alimiina catalyst for many days in making ethylene 
without noticing any deterioration. — E. E. R. 

*® A thoria catalyst may be cleaned by passing steam over it at 380^ till all 
volatile material is removed and following this with nitrogen peroxide at the same 
temperature as long as there is any action, the oxides of nitrogen being finally 
displaced by steam. A catalyst so regenerated is snow white and shows its origi- 
nal activity. — Krambb and RBm, /. Amer. Chem. Soc. 43, 884 (1921). 



255 DEHYDRATION 718 

Temperature C.c. per minute 

260** 5 

300*^ 17.5 

310** 27 

.330^ 48.5 

340** 57.5 

370^ 73 

But it must be remembered that for any given oxide, the elevation 
of the temperature tends to introduce and make more and more prom- 
inent the reaction of dehydrogenation. Thus at 340** tUania produces 
practically pure ethylene from alcohol, but at 340** with a more rapid 
evolution of gas there is some hydrogen, while at 360** the hydrogen 
amounts to one third of the gas.^^ 

Above 400** the gas produced may contain eihans along with the 
hydrogen.^ 

710. The presence of water in the alcohol is unfavorable to dehy- 
dration but does not interfere with dehydrogenation. Thus with 
alcohol diluted with its own volume of water, alumina gives a gas 
containing twice as much hydrogen as with absolute alcohol.^ 

711. Increase of pressure retards the dehydration of alcohols, or 
rather raises the temperature at which this takes place; the inter- 
mediate production of the ether from primary alcohols is favored by 
increase of pressure which is unfavorable to the separation of the 
hydrocarbon.** 

712. The dehydration of alcohols higher than propyl, effected by 
oxides or by other catalysts, usually leads to the production of several 
isomeric unsaturated hydrocarbons and frequently also to the for- 
mation of a certain proportion of polymers (211). 

713. Alumina. The best results are obtained with alumina precipi- 
tated from aliuninum nitrate by ammonia, well washed and dried at 300**. 

The dehydration of methyl alcohol begins at about 250** and is 
rapid below 300**, yielding exclusively methyl ether absorbable by con- 
centrated sulphuric acid. At about 350**, the ether is accompanied by 
a small amount of aldehyde, a little of which is condensed, and hydro- 
gen is collected containing carbon monoxide resulting from the partial 
decomposition of the formaldehyde. 

With eihyl alcohol, ether is formed above 240** and at 290** pure 
ethylene is evolved regularly, this evolution becoming rapid at 340^ 

^ Sabatieb and Mailhx, Ann, Chim. Phys. (8), aO| 325 (1910). 
«* Engbldbr, /. Phya. Chem., az, 676 (1917). 

« Ipatibf, /. Ruaaian Phya. Chem. Soc, 36, 786. and 813 (1904), C, 1904 (2), 
1020 and 38, 63 and 92 (1906), C, 2906 (2), 86 and 87. 



714 CATALYSIS IN ORGANIC CHEMISTRY 256 

It is not nece&fiary to go beyond 360^ where the ethylene begins to be 
decomposed and where its evolution slows down rather rapidly on 
account of the weakening of the catalyst/^ 

Propyl alcohol gives a regular current of propylene above 300^ 
without any of the ether. 

Normal and iso-lnUyl alcohols likewise give a regular evolution of 
hydrocarbons entirely absorbable by sulphuric acid. Both yield 
mixtures of the isomeric hydrocarbons, CJI^.^* However, Ipatief 
obtained pure isobutylene from isobutyl alcohol.^* 

With iaoamyl alcohol, the dehydration goes readily, the best yield 
being obtained between 500 and 540^. The product contains several 
isomeric hydrocarbons, CeHio, but the proportion of isopropyUeihylene 
is greater than in the dehydration by sulphuric acid.^ 

At 450^ secondary Imtyl alcohol gives pure butylene and tertiary 
butyl alcohol, or trimethyJrcarbinolf yields only isobutylene,** 

At a dull red, aUyl alcohol evolves quite pure propylene with a cor- 
relative production of acrolelne^^ 

714. Benzyl alcohol is readily dehydrated at above 300^ to form 
the yellowish resinous hydrocarbon (CTHe),, without evolution of 
gas.»« 

Other primary, secondary, or tertiary aromatic alcohols are read- 
ily dehydrated by alumina without complications below 350^, with the 
production of the corresponding unsaturated hydrocarbons. Thus 
pkenyl-benzyJrcarbinol, CeHs . CH (OH) . CH2 . CjHe, yields stiJbeney CJEIj . - 
CH : CH.C6H5, quantitatively." 

Bomed gives merUhene and the various secondary or tertiary 
cyclohexyl alcohols are readily changed to the corresponding cydohexene 
hydrocarbons. Thus cydohexanol is entirely transformed into cydo- 
hexene and LS-dimeOiyl^ydohexanol yields 1 .iHiimeOiylrcydoheocene,^ 

At 350^ and 30 to 40 atmospheres with alumina, decahydronaphthol 
yields octahydronaphlhalene, CioHie, boiling at 197°." 

715. Blue Oxide of Tungsten. Tungstic oxide is readily reduced 
by alcohol vapors above 250° and brought to the blue oxide^ inter- 
mediate between WOt and WO2, approaching the composition WjOs 

** Sprent, /. Soc, Chem. Ind,, 32, 171 (1913). 

^ SsNDEBSNS, BuU. Soc. Chim. (4), z, 692 (1907). 

*• Ipatibf and Sdzitoweckt, Berichte, 40, 1827 (1907). 

«7 Adams, Eamm and Marvel, /. Amer. Chem. Soc., 40, 1950 (1918). 

** Ipatief and Sdzitoweckt, BerichU, 40, 1827 (1907). 

«* Kbestinskt and Nixitinb, /. Russian Pkys. Chem, Soc,, 44, 471 (1912). 

*• Sabatieb and Mailhb, Ann. Chim. Phys. (8), ao, 298 (1910). 

*^ Sabatieb and Murat, Ann. Chim. (9), 4, 284 (1915). 

** Ipatief and Rutala, /. Russian Phys. Chem. Soc., 44, 1692 (1912). 

» Ipatief, BerichU, 43, 3383 (1910). 



257 DEHYDRATION 717 

more and more nearly, and which on exposure to the air, after cooling, 
reoxidizes spontaneously, more or less rapidly regenerating the original 
yellow oxide. 

This blue oxide is a mediocre catal3n3t for methyl alcohol which it 
does not attack till 330^, dehydrating and dehydrogenating it simul- 
taneously, but is an excellent dehydration catalyst, very active and 
very regular, for other alcohols. ^^ By using a train of blue tungsten 
oxide 51 cm. long at 340^ and vaporizing 17 g. of alcohol per hour a 
regular evolution of 101 cc. ethylene per minute containing only 1 or 
2 % of hydrogen, was obtained, 5.1 g. of the alcohol escaping decom- 
position. By doubling the rate of flow of the alcohol the evolution of 
gas reached 140 cc. per minute. 

At 320^, propyl, iscbuiyl and iaoamyl dlcohoU give good yields of 
the unsaturated hydrocarbons, and benzyl alcohol is rapidly trans- 
formed into crusts of the yellow pol3aner (714). 

716. Thoria. For all the alcohols, except methyl, thoria is a very 
regular catal3n3t, the properties of which have already been mentioned 
(708). 

With eihyl alcohol, the reaction begins around 280^ and is readily 
accelerated by rise of temperature. By using a boat containing 4.7 g. 
thoria, at 325^, 11 cc, and at 350^ 31 cc. of practically pure ethylene 
were obtained per minute. 

The results are equally good with propyl and isobiUyl alcohols and 
with the other alcohols mentioned under alumina. 

The secondary alcohol, iaopropyly begins to yield propylene at 260^. 

717. Mineral Salts. Clayy or hydrated aluminum silicate, and par- 
ticularly the white variety, kaolin, has a remarkable dehydrating 
power with alcohols.** 

The fragments of a graphite crucible (a mixture of graphite and 
clay) gave Ipatief a good yield of unsaturated hydrocarbons from 
alcohols.** 

In 1906, Bouveault noted the special activity of clay and designed 
an apparatus for using it for the dehydration of various alcohols quite 
similar to that which he employed for their dehydrogenation over 
copper (654). The catalyst consisted of clay balls about 1 cc. in 
volume, dried at 300^ in a current of air and packed in the 1 m. ver- 
tical tube of the apparatus in which about 1 k. of alcohol per day 
could be dehydrated. Ethyl, propyl, ieobutyl and cydohexyl alcohols 

^ Sabatibb and Mjoua, Ann, CUm, Phys. (8), ao, 328 (1910). 
H Kaolin was used as catalyst in preparation of ethylene at Edgwood Arsenal, 
U. 8. A., during the war. — E. E. R. 
•• IPATnur, BerichU, 36^ 1990 (1903). 



718 CATALYSIS IN ORGANIC CHEMISTRY 258 

are readily dehydrated by this means. In the case of isoamyl alcohol 
the hydrocarbons are isomerized as with alumina or zinc chloride.*^ 
All aluminum salts have more or less of the catalytic power of 
alumina. The basic almninmn sulphates obtained by calcining neutral 
aluminum sulphate at a dull red ** and likewise the mixtures of these 
with alkali sulphates obtained by calcining potassium and sodium 
alums have this power. 

718. ^ Calcium sulphate is a mediocre catalyst. When obtained by 
calcining gypsum at a moderate temperature, it gives with alcohol at 
420^ an evolution of ethylene containing 6 % of hydrogen, while if it 
is prepared at a red heat, it gives a very slow evolution of hydrogen 
containing 14 % of ethylene at 460**.** 

719. Aluminum phosphate is recommended as a good catalyst by 
Senderens, who explains this aptitude as a sort of culmination of the 
catalytic power of alumina and that of phosphorus.*^ Ethyl alcohol 
is decomposed above 330° and rapidly at 380^ With propyl, dehy- 
dration commences at 300° and is rapid at 340°; with buiylf the re- 
action is important at 320°. Isoamyl alcohol is attacked at above 300°, 
while 250° is high enough to decompose isopropyl, which goes rapidly 
at 300°. The decomposition of trimethyUcarbinol begins at 140°.*^ 

720. The Case of BenzhydroL We have noted above (692), that 
benzhydrol, C6H«-CH(OH)-C6H5, heated to 210° with copper powder 
gives the ether, ( (C«H6)sCH)sO, in 75 % yield instead of benzophenone. 
At a higher temperature, 290°, copper powder produces benzophenone 
chiefly with a slow evolution of hydrogen, along with a little of the 
ether and of diphenylmethane.^ 

In fact the alcohol is dehydrogenated to benzophenone but the 
liberated hydrogen is used for the most part immediately to form 
diphenylmethane and particularly symmetrical tetraphenyl-ethane : 

CeHs . CH (OH) . C«Hb - Hj + CJBe . CO . CeHj 
CeMs.CO.CeHs + 2Ms = I12O -I- Cells. CHs.CeMs 
2CeH,.C0.C«H, + 3H2 - 2H,0 + (C«Hb)2CH.CH(C6H,)2 

Dehydrating catalysts lead to the same result as copper. The 
vapors of benzhydrol passed over thoria at 420° give, vrithoul eUmi" 
nation of hydrogen, a mixture of benzophenone, diphenylmethane and 
82^.tetraphenyl-ethane with the separation of water simply.^ 

»' BouVBAUMP, Bvll 80c. Chim. (4), 3, 117 (1908). 

** Sabatier and Mailhi}, Ann. Chim. Phys. (8), ao, 300 (1910). 

•• Sendbrens, BvU. Soc. Chim. (4), 3, 633 (1908). 

•• Sbndbrens, BvU. Soc. Chim. (4), i, 690 (1907). 

*^ Sbndbrbnb, Compt. rend., 144, 1109 (1907). 

** KNOBYENAaBL and Hbckbl, BerichU, 36, 2816 (1903). 

•* Sabatibb and Mubat, Ann. Ckim, (9), 4, 282 (1915). 



269 DEHYDRATION 728 

721. Catalytic Passage from an Alcohol to the Corresponding 
Hydrocarbon. This passage is realized easily in two successive steps : 
1st dehydration of the alcohol over alumina or thoria to the unsat- 
urated hydrocarbon; 2nd hydrogenation of this hydrocarbon over a 
slightly active nickel at 200-60'' : 

CnHsn^lOH = CnHin "|" HjO 

alcohol 

CnHin + Hi « CnHsB+2 

A large number of syntheses of hydrocarbons in this way have been 
reported by Sabatier and Murat; for example, uns.diphenylrethane 
(C6H6)sCH.CHs was prepared from methylrdiphenyUcarbinol, (CaHfi)^- 
C(OH).Gn,.w 

722. The two reactions can be superimposed by submitting the 
alcohols to the simultaneous action of alumina and nickel, but a nec- 
essary condition is that the two reactions can be carried on at the 
same temperature which is usually impracticable at the ordinary pres- 
sure. They can be readily carried on simultaneously in the apparatus 
of Ipatief (586). Thus fenchyl alcohol (40 g.) with alumina (1.5 g.) 
and nickel oxide (2.6 g.) with hydrogen at 110 atmospheres for 40 
hours at 230^ gave a good yield of fenchane^ boiling at 162^, and 
caroomenihol gave menihane. 

Camphor, when treated under the same conditions at 220^, is 
changed into iaocamphene, melting at 63^. The succession is doubt- 
less:" 

CioHii^ ) CioHigO ► CioHie > CioHu* 

camphor bomeol oamphene oamphane 



Catalytic Dehydration of Poly-alcohols 

723. It is seldom that the dehydration of poly-alcohols leads to 
hydrocarbons; aldehydes and ketones are conunonly formed. 

However, it has been found that when the vapors of H-meihyU 
biUane-diol{l .S) are passed over kaolin at above 400^, isoprene is 
formed :•• 

HOCH, . CH (CH,) . CH (OH) . CH, - 2H,0 + CH, : C (CH,) . CH : CH». 

Quiniie, CcHio(OH)s, submitted to the action of alumina at 360^ 
and 30 to 40 atmospheres pressure, is dehydrated to dihydro-bemene, 

*^ Sabatddb and Murat, Ann. Chim. (Q), 4, 254 (1915). 

•* Ipatixf and Matow, Berichie, 45, 3205 (1912). 

u Etbiaxidxs and Eablb, U. 8. Patents, 1,094,222, 1,094,223 and 1,106,290. 



724 CATALYSIS IN ORGANIC CHEMISTRY 260 

CcHs, along with some tetrahydrchphenolf CA.OH, resulting from the 
incomplete dehydration.*^ 

724. Glycol, HOCHj.CHjOH, heated at 400^ with alumina yields 
chiefly acetaldehyde which condenses partially to paraldehyde. 

Pinacone, (CH,),C (OH) .C (OH) (CH,),, is changed at 300-20' into 
pinacoline as it is by the action of dilute sulphuric acid.*^ 

725. Glycerine in the liquid form to which are added small 
amounts of alumina, aluminmn sulphate or potassimn bisulphate, is 
dehydrated to acroleine at about 110' : 

HOCH,.CH(OH) .CH2OH - 2H2O + CH, : CH.CHO. 

To 100 parts of glycerine, 4 parts anhydrous aluminum sulphate, 
8 parts of the hydrated, or 5 of potassium bisulphate are used. The 
yield is 17 to 19 %, or a little smaller than when 227 parts of bisul- 
phate are used as in the ordinary method.** 

This process has the inconvenience that acetaldehyde and sulphur 
dioxide are evolved; the same is true when these catalysts are re- 
placed by ferric or cupric sulphaies. 

Better results are obtained with anhydrous magnesium stdpJuUef 
with which more than 50% of the theoretical yield is obtained at 
330-40', with negligible amounts of by-products, while at 360' acet- 
aldehyde appears.^* 

726. Ddiydration in the Gaseous Phase. When the vapors of 
glycerine are passed over alumina at about 360', complete dehydra- 
tion to acroleine takes place, but a portion of this is decomposed into 
ethylene and carbon monoxide while another portion is crotonized to 
higher aldehydes which condense along with the water and acrolelne.^^ 

When for the alumina catalyst is substituted black uranoue oxide, 
which dehydrates and dehydrogenates alcohols at the same time, with 
a predominance of the latter reaction (675), results intermediate 
between those with alumina and those with copper (680) are obtained. 

By using kaolin at 380-400' or aluminum phosphate at 450' we can 
transform butane-diol{LS) into butadiene regularly or penlane^iol- 
(£4) iiito piperylene. The presence of a little hydrobromic acid or of 
aniline hydrobromide increases the yield which for piperylene reaches 
50%. 

" Ipatddf, BerichU, 43, 3383 (1901). — /. Buasian Phys. Chem. 80c., 43, 1552 
(1911). 

•* Ipatixf, /. Russian Phys, Chem, Soc., 38, 92 (1906). 

•• Sbndbbsns, BuU. 80c. Chim. (4), 3, 828 (1908). — Campt. rend., 151, 530 
(1910). 

'* WoHL and Mtlo, BsrichU, 45, 2046 (1912). — Witzbiiann, /. Amer. Chem. 
80c., 36, 1766 (1914). 

" Sabatibb and Gaudion, Campt. rend. z66, 1034 (1918). 



261 DEHYDRATION 737 

Pinacone is likewise dehydrated to dimdhyl-iiUadiene when its 
vapors are passed over copper at 430-500'' and the yield is raised to 
70 % by the presence of a little hydrobromic acid." 

727. Ring Foimalion by the Dehydration of Poly-akohols. Long 
chain molecules containing several alcohol groups can pass into the 
furfurane ring by catalytic dehydration in solution. 

Arabinose, HOCH,. CH (OH) . CH (OH) . CH (OH) . CHO, when 
boiled with sulphuric acid diluted to one third, is converted into 
fvirfvrdl,^ 



CH C-CHO 
\0/ 

Mucic acid or saccharic acid, HOOC. (CH0H)4.C00H, heated to 
lOO'' with hydrochloric acid, loses two molecules of water to form 
dehydro^mudc or furfw'anfhdicarbimic acid : '^ 

CH CH 



[ooo/x)/xx)0] 



^ ETBiAKmns, /. Amer. Chem, Soc,j 369 980 (1914). 
^ Stonb and Tollbns, Annailen^ 349, 237 (1888). 
'« YoDSB and Tolubns, BmchU, 34, 3446 (1901). 



CHAPTER XVI 

DEHYDRATION (Continued) 

§ 2. — ELIMINATION OF WATER BETWEEN AN 
ALCOHOL AND A HYDROCARBON 

728. Thb use of anhydrous aluminum chloride enables us to 
condense an aromatic alcohol with an aromatic hydrocarbon in the liquid 
phase. Thus bemyl alcohol, CaHB.CHsOH, and benzene give diphenyU 
methane, CeHt.CHs.CeHB, accompanied by a certain amount of oriho 
and para dibenzyUbenzenes and other hydrocarbons among which is 
found anthracene.^ The same reaction takes place with secondary 
aromatic alcohols which yield tertiary hydrocarbons. With benzene 
we have : 

/R 
CeH5.CH(0H) .R + C«H« = H^O + C«H6.CHC 

The yield is better when R is an aromatic residue than when it is 
methyl or specially ethyl. The use of an excessive quantity of alu- 
minum chloride, particularly if the temperature is high, may lead to 
the elimination of a phenyl group or of an aliphatic residue, R.* 

By adding aluminum chloride to a mixture of methyl-^henyU 
carbinol, C6H6.CH(OH).CH8, and benzene kept at 25-35°, a 20% 
yield of diphenyUelhane is obtained along with etiiyUbenzene, diphenyU 
msthane, and anthrax:ene, due to a further action of the chloride. By 
operating at 10° with 5 molecules of benzene and 0.5 of aluminum 
chloride a 65 % yield of diphenyl-ethane is obtained. 

Under the same conditions, eihyJrphenyJrcarbinol forms diphenyl- 
propane in 40 % yield. 

Benzhydrol dissolved in 5 molecules of benzene to which is added 
1 molecule of aluminmn chloride at 35-40°, gives a 40% yield of 
triphenyUmethane with some diphenyl^msthane. By operating below 
10°, the yield of triphenyl-methane reaches 65 to 70%.' 

^ Huston and Fribdbmann, /. Amer, Chem, Soe,, 38, 2527 (1916). 

* Huston and Fbibdemann, /. Amer. Chem, 80c,, 4O9 785 (1918). 

* Huston and Fbikdbmann, /. Amer. Chem, Soc.^ 40, 785 (1918). 

262 



263 DEHYDRATION 781 



§ 3- — ELIMINATION OF WATER BETWEEN AN ALCOHOL 

AND AMMONU OR AMINES 

Reactions in Liquid Systems 

729. The primary alipliatic dlcohola heated for several hours at 
220^ in an autoclave with aniline and a very small amount of iodine 
as a catalyst, give good yields of the corresponding aUcyUanUinea.^ 

Thus by heating equal molecules of aniline and methyl alcohol for 
9 hours at 230^ with 1 % of iodine, a yield of 73 % of msthyUaniline is 
obtained. By using 2 molecules of the methyl alcohol, 86 % of dimethyU 
aniline is obtained in 7 hours under the same conditions. 

By heating 1 molecule of aniline and 4 molecules of ethyl alcohol 
with 0.5 g. iodine 10 hours, 95% of diethyUaniline is obtained. 

Under the same conditions, bemyl alcohol and aniline give benzyU or 
dibemyUaniline and isoamyl alcohol furnishes amyU and diamyUanilines. 

With alcohols and a little iodine, a- and P-naphlhyUaminea react 
similarly. 

730. Aromatic Alcoholis may condense with aniline or its homologs 
when they are heated gently with dUvle hydrochloric add.^ Thus tet- 
ra^^methyUdiamino-benzhydrol, (CH8)tN . C0H4 . CH (OH) . C^ . N {CHz)%, 
eliminates a molecule of water with aniline to give tetramethylrleuo' 
anUine, ((CH,)2N.CeHi),CH.C«H4.NH,. 



Reactions in Gaseous Systems 

731. We have seen above that the cataljrtic dehydration of alco- 
hols by various anhydrous metallic oxides has been explained by 
Sabatier and Mailhe on the assumption of the formation of a sort of 
unstable ester between the alcohol and the oxide acting as an acid, 
e.g. an alcohol thorinate (603). 

But according to the fundamental method of Hofmann, ammonia 
acts on the esters of mineral acids to form amines. Sabatier and 
Mailhe have imagined that the unstable esters formed with the oxides 
should behave in the same way. It was to be hoped that, at least for 
some oxides, the reaction of ammonia with the temporary ester should 
be more rapid than the decomposition of this ester into an ethylenic 
hydrocarbon.* 

« Knobysnagsl, /. prakl, Chem. (2), 89, 30 (1914). 

• Badischs, German PaterU, 27,032 (1883). 

* Sabatibb and Mailbb, Compt. rend., 150, 823 (1910). 



732 CATALYSIS IN ORGANIC CHEMISTRY 264 

Experiment has fully verified this expectation. Thus with thoria 
and an aUphatio alcohol we have : 

2CnHjH-iOH + ThO, = H,0 + T1iO(OC.Hto+i)t 

thorinato 

Then : 

ThO(OCnHfc,+0t + 2NH, - H,0 + HCnHft,+i.NH, + ThOt 



a succession of reactions which is equivalent to the sii^e reaction : 
C«Hfc,+i .OH + NH, « H,0 + CaHft,+i .NH,. 



732. This reaction does not take place in the absence of a catalyst, 
but does go well in the presence of thoria at 300-50^, the dehydration 
into an unsaturated hydrocarbon being only a side reaction. Thus with 
ethyl alcohol, which is largely broken down to ethylene by thoria at 
350^, the presence of ammonia almost completely prevents the evo- 
lution of the hydrocarbon but causes the production of ethyJramine. 
The same is true with other dehydrating catalysts, alumina, blue oxide 
of tungeien and equally with the mixed catalysts, such as tiUinia, 
chromic oxide, blue oxide of molybdenum, zirconia, etc. The formation 
of the amine directs the activity of the catalysts to its profit : the 
decomposition of alcohols into aldehydes and hydrogen as well as into 
water and ethylenic hydrocarbons is almost suppressed and the for- 
mation of the amine predominates. 

Furthermore the primary amine thus produced reacts in its turn on 
the alcohol in the presence of the catalytic oxide as does ammonia, 
and forms the eecondary amine: 

aH,a+i.OH + CaH,„+i.NH, = H,0 + (aH*.+02NH 

and there is the possibility of the formation of some tertiary amine by 
the action of the secondary on the alcohol. 

733. The direct action of ammonia gas on alcohols is a general 
method for Oie preparation of amines. Into a tube containing several 
grams of thoria heated below 350^ (from 250 to 350^ according to cir- 
cumstances) are passed at the same time alcohol vapors and ammo- 
nia (furnished very conveniently by a cylinder of liquid anmionia). 
The liquid condensed at the other end of the tube is a mixture of 
ammoniacal water, primary and secondary amines (with traces of 
tertiary) and untransformed alcohol holding in solution a certain 
amount of the ethylenic hydrocarbon. The latter products are easily 
separated from the amines by fractional distillation.^ 

From propyl alcohol, mono- and dipropyUaminea can be readily 
prepared and mono- and dvisoamyUamines from isoamyl alcohol. 

' Sabatddb and MAn«HB, Compi. rend., 148, 898 (1909). 



265 DEHYDRATION 788 

734. likewiae benzyl alcohol and ammonia with thoria at SOO-SSO** 
give only a small amount of the resinous hydrocarbon (CrHe),, but 
yield chiefly benzyU and dibenzyUaminea, and a small amount of 
tribenzyUaminef which solidifies in the condenser tube. By operating 
at 330^, ben^yl-amine is the main product, while at 370-380^, dibensyl- 
amine predominates, but there is at this temperature a notable decom- 
position of the alcohol to the aldehyde, which, in turn, is split into 
benzene and carbon monoxide.^ 

735. The secondary alcohol, isoprapyl, does not suffer appreciable 
dehydration over thoria at 250^, but at that temperature ammonia is 
effective and gives about 20 % of isopropyUamine accompanied by a 
little di'daopropyUamine. Around 3W a considerable evolution of 
propylene is observed and the condensed liquid contains about one 
third isopropyl-amine and about the same amount of secondary, along 
with water and unchanged alcohol.* 

Likewise diethyJrcarbinol and dipropyUcarbinol give mixtures of the 
corresponding primary and secondary amines.^* 

736. The method is less easy to apply to bemhydrol: yet its 
vapors when carried by an excess of ammonia over thoria at 280^ give 
some bensihydryl-amine, but dehydration preponderates producing 
tetraphenyUeOiylene. 

737. The secondary cydohexane alcohols (cyclohexanol and its 
homologs) are dehydrated rapidly in contact with thoria at 300-350^ 
but in the presence of ammonia at 290-320^ the reaction is, for the 
most part, directed toward the formation of amines, hardly more than 
30 to 40% of the unsaturated hydrocarbons being simultaneously 
produced. 

In this way cydoheo^UaminB and the three methyUq^doheo^lr' 
amines have been prepared, some of the secondary amines being 
formed in all cases. ^^ 

738. Mixed Amines. In this reaction the ammonia may be re- 
placed by a primary aliphatic amine which gives us a method of 
preparing mixed secondary amines. It is sufBicient to pass a mixture 
of a primary amine and an aliphatic, aromatic, or cyclohexyl alcohol 
in equivalent amounts over thoria at about 320''* Among the aliphatic 
alcohols, methyl gives the poorest results. Eihyl4soamyUamine, boil- 
ing at 126% propyl4eoamyUamine, boiling at 145^, and isobiUylrieoamyU 
amine, boiling at 158% have been prepared in this manner." 

* Sabatisb and MAn<HB, Compl. rend., 153, 160 (1911). 

* Sabatddb and Mailhs, Campl, rend., 153, 1204 (1911). 
i« Mailhb, BvU. 80c. Chim. (4), 15, 327 (1914). 

^ Sabatisb and Mau^hb, Campl, rend., 153, 1204 (1911). 
" Sabatibb and Mausb, Compi. rend., 14S, 900 (1909). 



789 CATALYSIS IN ORGANIC CHEMISTRY 266 

739. By associating cydohexylraminB with various aliphatic alco- 
hols, with benzyl alcohols, and with cyclohexanol and its homologs, a 
large number of mixed secondary cyclohexyl-amines can be prepared.^ 

Thus methyl alcohol gives melhyJrcyclohexylraminef boiling at 145^, 
while ethyl and other primary alcohols give the corresponding mixed 
amines with still better yields. Isopropyln^ycbhexyl^ifnine ^^ and 
benzyl<yclohexylramine8 have been made thus. 

Cyclohexanol itself gives di-^dohexylramine identical with that ob- 
tained in the hydrogenation of aniline (466). The three methylcydo' 
hexanola give the three methylcyclohexyl-cyclohexyl-amines.** 

740. At higher temperatures the aromatic amines can undergo 
similar reactions. By passing over alumina at 400-430^ a mixture of 
aniline vapors and methyl alcohol in excess, the immediate formation 
of methyl-aniline is obtained and of dimethylranUine, resulting from the 
action of the methyl alcohol on the methyl-aniline. 

Likewise o.toluidine is completely transformed by methyl alcohol 
over thoria into methyl-^.toluidine and then into dimethyUo.ioluidine. 
Similar results are obtained with meta and para toluidinea. A single 
passage over the catalyst produces about equal proportions of the 
mono- and di-methyl compounds, and a second passage completes the 
substitution. 1* 

By causing ammonia to act on a mixture of two alcohols, the pri- 
mary and secondary amines corresponding to each alcohol are obtained 
and some of the mixed secondary amine. This has been found true 
with a mixture of propyl and isoamyl alcohols at 330^. 

741. Alkyl-piperiiUnes. The above method can be applied to 
piperidine with various alcohols over thoria at 350^. The results are 
satisfactory with propyl alcohol which yields only a little propylene 
and gives N-propyJrpiperidine, boiling at 149**, and with isoamyl alco- 
hol which furnishes N-dsoamyUpiperidine, boiling at 186^, but are poor 
with cyclohexanol which gives much cyclohexene and only a httle 
N-cyclohexylrpiperidin/B, boiling at 216**.*^ 

742. PyiroL An analogous reaction is carried out by the aid of 
zinc dust with a mixture of ethyl alcohol and pyrrol which give a-ethyU 
pyrroU^ 

^ Sabatdbb and Mailhb, Compi. rend,, 153, 1207 (1911). 
^* Mailhb and Ahoboitx, BuU. Soc, Chim, (4), 15, 777 (1914). 
^ Sabatieb and Mailhb, Compi, rend,, 153, 1207 (1911). 
^* Mailhb and db Godon, Compt, rend,, 166, 407 and 564 (1918). 
" Gaudion, Btdl, Soc. Chim. (4), 9, 417 (1911). 

i« Dbnnstbdt, Berichte, 23, 2563 (1890). — Zanetti, Qaz, Chim, Ital,, az (2), 
167 (1891). 



267 DEHYDRATION 744 



§ 4* — ELIMINATION OF WATER BETWEEN AN 
ALCOHOL AND HYDROGEN SULPHIDE 

Synfliesis of Mercaptans 

743. If the direct action of alcohols on the dehydrating oxides, 
such as thoria, gives rise to the formation of a sort of unstable ester 
{{horinate)f it can be predicted that when this is brought into contact 
with an acid more energetic than the hydrate of the oxide, such acid 
will displace the oxide at least in part to give a new ester. We will 
have: 

ThO(OCnHfa+i)t + 2AH = 2A.CnHan+i + ThO, + H2O 

thorinato ester 

and if the acid is incapable of forming a stable salt with thoria as a 
base, the thoria will be regenerated and will react with a new portion 
of alcohol to repeat the cycle. 

Sabatier and Mailhe beUeved that hydrogen sulphide, which does 
not react with thoria (nor with alumina), would act in this manner, 
since it appears to be a stronger acid than thoria. We would have 
in succession: 

ThO(OCnHto+i)t + 2BS = 2CnHfa.fi.SH + ThO, + H2O 

thorinate meroM^tan 

and then, with greater difficulty, on account of the acid function still 
remaining in the mercaptan: 

ThO(OCaHfa+i) « + 2CnHfa+i.SH = 2(CnHfa+i),S + ThO, + HjO. 

thorinate 

The thoria being regenerated can react with a fresh portion of 
alcohol and if the hydrogen sulphide continues to act, the thoria can 
function indefinitely as a catalyst to produce mercaptans and alkyl 
sulphides, provided that the reaction of the hydrogen sulphide on the 
unstable thorinate is more rapid than the decomposition of the tho- 
rinate into the unsaturated hydrocarbon, water and thoria. 

744. Experiment has shown that this is usually the case. This is 
a direct method for the preparation of mercaptans from the alcohols. 
It is sufficient to pass a mixture of the alcohol vapors and hydrogen 
sulphide over a train of thoria maintained between 300 and 380^. 
The mercaptan along with a small amount of the neutral sulphide is 
condensed with the water and unchanged alcohol. 

A portion of the alcohol is dehydrated to the unsaturated hydro- 



746 CATALYSIS IN ORGANIC CHEMISTRY 268 

carbon, but with the primaiy aliphatic alcohols this is not important, 
provided the reaction temperature is not too high, but it is consid- 
erable with the secondary alcohols which decompose into hydrocarbons 
more readily. 

Methylf ethyl, propyl, iaobtUyl, and isoatnyl mercaptans have been 
thus prepared with yields above 75 %, so long as the condensation of 
the products is efficient. The yield is equally good for aUyl mercaptan 
from allyl alcohol. Benzyl alcohol gives a rather large proportion of 
benzyl mercaptan and some sulphide.^* *^ 

745. The yields are less satlrfactory, hardly above one third, when 
secondary alcohols are used. The following mercaptans have been ob- 
tained in this way: propane-4hiol{2), perUane^iol{S), heptan^-thioliS), 
;?.^-<iime^2/I-pentone-^u)I(S), cydohexyl mercaptan and the three o.m. 
and pjmathylrcydohexyl mercaptans,*^ and also the mercaptan from bensh 
hydrol, C«H5.CH(SH).C6H5, boiling at 278^« 

746. Various other catalytic oxides have been found to be inferior 
to thoria. With isoamyl alcohol and thoria maintained at 370-80^ 
the approximate yields of mercaptans for 100 parts of alcohol de- 
stroyed were: 

Thoria 70 

Zirconia 44 

Uranous oxide 30 

Blue oxide of tungsten 22 

Chromic oxide 18 

Blue oxide of molybdeniun 17 

Alumina 10 

Alumina gives amylene chiefly.^ 

^* Sabatixb and Mailhb, Campi. rend,, 150, 1217 (1910). 

*« Working at 360-380'' Eraiosb and Reid [/. Amer, Chsm. 80c, 43, 887 (1921)], 
obtain the following yields from the alcohols named: methyl 42 %, ethyl 35 %, 
propyl 46 %, n.butyl 52 %, isobutyl 36 %, isoamyl 42 %. A part, at least, of the 
discrepancy between these figures and those given by Sabatier and Mailhe ia due 
to a different method of estimating the mercaptan produced. 

They find that the amounts of unsaturated hydrocarbons formed are surprisingly 
low, usually only 2 to 3 %, while considerable amounts of the aldehydes, 7 to 15 % 
(estimated by the hydrogen produced), are formed. — E. E. R. 

» Mailhb, BvU, Soc. Chim. (4), 15, 327 (1914). 

" Sabatibb and Mailhb, BvU. Soc. CUm, (4), 11, 99 (1912). 

** Sabatibb and Mailhb, Compl. rend., 1501 1569 (1914). 



269 DEHYDRATION 760 



§ 5- — BLDflNATION OF WATER BETWEEN ALCOHOLS 

AND ACIDS 

Esterification 

747. It is known that the formation of esters by the direct action 
of organic acids on alcohols takes place very slowly at ordinary tem- 
peratures and that the transformation is never complete as it is limited 
by the inverse action of water on the ester. Several years of contact 
are required for this limit to be reached. Elevation of the tempera- 
ture hastens the reaction greatly but it still requires considerable time, 
several days at 110^, several hours at 156^. 

The production of ester is very slow in the gaseous state also, even 
at temperatures above 250^: when a mixture of equivalent amounts 
of the vapors of ethyl alcohol and acetic acid is passed through a tube 
heated above 250^, the esterification effected is entirely negligible. 

But either in the liquid or in the vapor condition, the presence of 
small amounts of catalysia accelerates the production of ester enor- 
mously so that the limit is soon reached. 

Esterification by Catalysis in the Liquid State 



748. The catalysts for esterification in liquid system are chiefly the 
strong mineral adds, hydrochloric and sulphuric, and several salts, 
ammoniufn salts, alkaline bisulphates, zinc chloride, sodium acetate mixed 
with water. 

749. Catalysis by Mineral Adds. When equal molecules of ethyl 
alcohol and acetic acid are mixed and the mixture is distilled, the 
amount of ester produced is less than 1 %. 

But a long time ago, Berthelot found that it is sufficient to add to 
a mixture of an organic acid and an alcohol a few per cent of hydro- 
chloric or sulphuric add to cause an abundant formation of ethyl 
acetate, benzoate, etc.'^ He showed that traces of stdphuric add are 
sufficient for the preparation of ethyl acetate.'* 

750. To a mixture of equal molecules of ethyl alcohol and acetic 
acid (106 g.) small quantities of hydrochloric add were added, 
namely: 

To the first 0.67 g. or 0.017 molecule 

second 4.77 g. or 0.125 molecule 

third 11.84 g. or 0.33 molecule 

M BxBTHXLOT, Btdl. Soe. CMtn. (2), 31, 342 (1879). 

» Bbbthblot and Jungflbibch, TraU4 de Chim. Organ., 3rd Ed. 1886, I, 208. 



761 CATALYSIS IN ORGANIC CHEMISTRY 270 

The amounts of ester formed were as follows : 

At ordinary temperature 

First Second Third 

Immediately after mixing 9.6 % 58.7 % 82.3 % 

After six hours 9.6 73.6 75.8 

The limit without the mineral acid would be 66.6%: this limit is 
raised by the presence of the hydrochloric acid,** and is practically 
attained in six hours with the above mixtures. In the cold, without 
this acid, several years would have been required. Besides, no ethyl 
chloride was formed. 

751. Analogous results were obtained with sulphuric acid. To a 
mixture of 1 mol. ethyl alcohol, 1 mol. acetic acid and 0.5 mol. water 
was added 0.02 mol. (about 2 g.) sulphuric acid and in 24 hours in the 
cold, the esterification had reached 59.6 %. In 2 hours at 100^, 60.6 % 
was reached, which is the limit for this system.*' 

By boiling under reflux a mixture of 25 cc. propionic add^ 25 cc. 
propyl alcohol, and 50 cc. 5 % avlphuric acid, the proportion of ester 
was:" 

After 0.5 hour 45.1 % 

1 hour 51.8 

2 hours 56.9 

3 hours 58.3 

752. The action of the sulphuric acid can be explained by the for- 
mation of add ethyl sulphate, the immediate product of the action of the 
sulphuric acid, and the action of which on the acetic acid would pro- 
duce ethyl acetate and regenerate sulphuric acid, which would renew 
the action. In the case of hydrochloric acid, Berthelot explains the 
accelerating action by assuming the formation of an addition product 
of the hydrochloric acid and the alcohol.** '* 

Bodroux has proposed a different explanation based on the tem- 
porary formation of an addition compound of the mineral acid cata- 

M Bbbthelot explainiBd the elevation of the limit by the taking part of the 
hydrochloric acid in the equilibrium, in which it increases the total amount of acid 
relative to the alcohol. 

" Bbrthxlot, BuU. Soc. Ckim. (2), 31, 342 (1879). 

** BoDBOUx, Compi. rend.f 157, 939 (1913). 

*• Bbrthelot, BvU, Soc. Ckim, (2), 31, 342 (1879). 

*^ It is curious how many chemists have given entirely different explanations 
for the action of hydrochloric and sulphuric acids. All the facts go to show that 
all acids act alike and that whatever explanation is given in any one case must fit 
all others. — E. £. R. 



271 DEHYDRATION 766 

lyst with the organic acid considered as the anhydride of an ortho 
acid: 

aO /OH 

AH + R.Cf =R.C^OH 
\0H \A 

/OH /OH 

then: R.C^OH + R'OH = AH + R.CH>H 

\A \0R' 

and finally by the immediate spontaneous loss of water: '^ 

>^(0H), 
R.Cf =H20 + R.C0.0R'. 

\0R' 

753. Many chemists still continue to think that the presence of a 
large amount of the mineral acid is favorable to esterification and it 
has become conmion usage to saturate the mixture of alcohol and acid 
with hydrogen chloride when preparing esters. Many seem to have 
forgotten that the same end can be attained by employing very small 
proportions of acids as catalysts. In 1895 Emil Fischer and Speier 
made exact measurements on this matter and showed that the use of 
small quantities of the mineral acids makes the operation more con- 
venient and leads to satisfactory yields.** 

754. Thus for the preparation of eihyl bemoate, the classical 
method was to saturate with hydrogen chloride a mixture of 1 part of 
benzoic acid with 4 parts ethyl alcohol, which gave only 73 % yield. 
Erdmann reconunended heating on the water bath for 10 to 12 hours 
1 part of the acid, 0.8 of alcohol and 0.4 of concentrated sulphuric 
add, the yield being 75%. 

By dissolving 3% hydrogen chloride in a mixture of 2 parts of 
alcohol to 1 part of acid, Emil Fischer obtained 76% of the ester, 
while for 1 % hydrogen chloride, the yield was 64.5 % for the same 
time of heating. 

755. The use of sulphuric acid is very advantageous. A mixture 
of 1 part of benzoic acid, 2 parts of alcohol and 0.2 part concentrated 
sulphiuic acid as heated 3 hours under reflux and a practical yield of 
90 % is obtained. If account is taken of inevitable losses during the 
washings, the yield is practically quantitative and as the excess of 
alcohol can be recovered almost entirely, the operation is very advan- 
tageous economically. 

n BoDBOUX, Compi. rend., 157, 1428 (1913). 

** E. F18CHEB and Spbibb, BeriehU, aS, 3262 (1895). 



766 CATALYSIS IN ORGANIC CHEMISTRY 272 

756. Emil Fischer has shown that this process can be applied not 
only to the aliphatic adds as Berthelot had found, and to benzoic 
add, but also to a large number of types of adds whether aliphatic or 
aromatic : 

Monobasic acids {naphihoiCy phenylracetic) ; 

Unsaturated monobasic acids {crotoniCf cinnamie) ; 

Saturated dibasic adds {succinic, phihalic), or unsaturated (fumaric) ; 

Hydroxy-acids (glycolic, phenylrglycolic) ; 

Phenol-adds (salicyhc); 

Ketone-acids (laevulinic) ; 

Polybadc hydroxy-adds {malic, tartaric, citric, mucic). 

The 3delds obtained are usually very satisfactory ; we quote some 
of the results obtained by heating for 4 hours a mixture of 1 part of 
the add with 3 to 4 parts of ethyl alcohol. 

% Catalyst % Ester 

a-Naphthoic add 2.2 HCl 74.8 

Phenyl-acetic 2.2 HaSO* 87.0 

Cinnamie 0.7 HCl 78.8 

Cinnamie 7.6 HaSO* 89.7 

Crotonic 7.5 HjSO* 64.3 

Phenyl-glycolic 2.2 HCl 67.6 

Laevulinic 0.7 HQ 76.6 

Succmic 0.8 HQ 73.9 

Succinic 8.0 HaSO* 73.9 

Fumaric 0.8 HCl 68.2 

Tartaric 0.8 HCl 72.8 

MaUc 0.8 HCl 70.5 

757. To obtain slightly soluble esters, Bodroux adds to a mixture 
of an organic acid and alcohol its weight of pure commercial hydro- 
chloric add diluted with its own volume of water: in the cold the 
mixture becomes turbid in a few hours and finally gives 60 to 90 % of 
ester. This process works well for phenyUacetic acid with various 
saturated alcohols but not so well for benzoic, salicylic and cinnamie 
acids}* V 

The yields are less satisfactory, hardly more than 50 %, with allyl 
alcohol or with the secondary alcohols, isopropyl and cydohexyl. They 
are worse still with dimeihyl^Oiyl<arbinol as well as with glycerine and 
mannite.*^ 

** BoDROTTX, Compt. rend,, 157, 939 (1913). 
M BoDBOTTX, Compi, rend,, 157, 1428 (1913). 



273 DEHYDRATION 769 

758. Senderens and Abonlenc, who do not seem to have known of 
the work of Berthelot and of Emil Fischer, have described as new the 
method of direct esterification of alcohols in presence of small amounts 
of sulphuric acid. The results which they give are a verification and 
extension to other alcohols of a part of the results of Emil Fischer. 
But they have thought that they were able to make an essential dis- 
tinction in the mechanism of the reaction between the aromatic adds 
that can be regarded as substitution products of acetic add, e.g. 
phenyjrocetie, on the one side and straight aromatic adds in whidi the 
carboxyl is attached to the nudeus, e.g. benzoic and tdtttc, on the other. 

For the first class, they consider the speed* of the esterification and 
the amount of ester formed as independent of the amount of the sul- 
phuric add, while for benzoic add, for example, these increase with 
the amount of the add, ''which consequenUy does not act rimply as a 
catalyst^* 

This distinction can not be admitted. A solid catalyst, up to a 
certain limit, acts in proportion to its active surface. Soluble cata- 
lysts, such as diastases or adds in hydration reactions, or sulphuric 
add in this case, act proportionally to their mass, at least if this is not 
too large for the total volume of liquid, and this is as true for acetic 
as for benzoic. The results quoted above from Berthelot for the for- 
mation of ethyl acetate in the presence of hydrochloric add, show 
that, in the cold, the rapidity of the esterification is approximately 
proportional to the amount of the catalyst. 

The difiFerence between the aliphatic adds and their analogs and 
benzoic add is that the velocity of the esterification of the former by 
the catalytic acid is much greater than for benzoic.'* To obtain the 
same yield of ester from benzoic a larger amount of the catalyst would 
have been required. 

Oxalic add is esterified regularly Uke succinic. 

Furthermore the practical 3delds are much better with the higher 
alcohols since with the less soluble esters the losses in the necessary 
washings with water and alkaline carbonate solutions are less serious. 

759. According to the same authors the sidphuric add can be re- 
placed by double its wdght of anhydrous aluminum sulphate or potas- 
sium bisvlp?iate^^ 

** The Blownees of esterification of benzoic add as compared with acetic add is 
shown by the work of Fsbas and Rbu), [[(/. Amer, Chan, Soe,, 40, 569 (1918)3i who 
found it necessary to heat benzoic acid with methyl and ethyl alcohols to 200* for 
96 hours to insure reaching the limit of esterification while Bbbthblot and St. 
GiLLBS found 24 hours sufficient even at 170*. — E. E. R. 

** SrarDBBSNs and AbouubnCi Ccmpt. rend., 153, 1671 and 1866 (1911) and 
I53t 881 (1911). 



760 CATALYSIS IN ORGANIC CHEMISTRY 274 

760. Glycerine mixed with acetic acid (1 molecule of glycerine to 
3 of the acid) gives on boiling under reflux for 1 hour, esterification 
amoimting to 0.4 molecule of acid: by the addition of 5% potassium 
bistdphate, the amount estenfied reaches 1.2 molecules. 

With 2 % anhydrous aluminum sulphate 1.5 mol. 

1 % sulphuric add 1.5 mol. 

By starting with 1 molecule of glycerine and 12 acetic acid, the 
amount esterified by boiling 1 hour is : 

With the aluminum sulphate 2 mol. acid 

sulphuric acid 3 mol. acid 

Triacetine is thus reached and there would be no advantage in 
increasing the amount of the catalyst.'' 

761. Esterification by Acetanhydride. A common method of pre- 
paring the acetates of alcohols or of poly-alcohols is to heat them with 
acetanhydride. 

R.OH + (CH,.C0)20 - 2CH,.C02R + HjO." 

By this means all the hydroxyl groups of a complex molecule are 
esterified. The presence of a certain amount of sodium acetate favors 
the action of the anhydride. 

Still better results are obtained by adding to an alcohol four times 
its weight of acetanhydride and a small fragment of fussed zinc chloride. 
The reaction becomes very rapid immediately. In the case of glyo- 
erine a veritable explosion is caused. With mannite, however, it is 
regular and yields in a few minutes mannite hexa-^xetate, melting at 
120V» 

Catalytic Esterification in Gaseous System 

762. The assumption of an unstable combination between the 
dehydrating oxides and the alcohols has been a basis for the prediction 
of various reactions which have been realized by experiment, such as 
the formation of mercaptans and aliphatic amines. Sabatier and 
Mailhe thought that it might be expected that these combinations 

" Senbebbns and Aboulbnc, Compt. rend., 158, 581 (1014). 
>s I think it better to write the reaction thus: 

R. OH + (CH«. C0),0 - CHtCftR + CHtCftH. 

An excess of the anhydride is always used and the reaction goes to completion 
since no water is formed to reverse it. — E. E. R. 
*• Franchimont, BerichUt xa, 2059 (1879). 



275 DEHYDRATION 764 

would play a part analogous to that of the acid sulphuric esters, that 
iSy that the dehydrating oxides would act as e8terifi4Mtian catalysts .^^ 

763. As has already been indicated, if a mixture of the vapors of 
an alcohol and an organic add be passed through a 60 cm. tube heated 
between 300 and 360^ the proportion of ester formed during the pas- 
sage is absolutely negligible, but the presence of a catalytic oxide 
changes the case entirely. Let us suppose that the tube contains a 
catalytic oxide, MO, derived from the metallic hydroxide, M (OH)s, an 
amphoteric hydroxide. 

The reaction can take three difiFerent courses: 

1st. The add may combine to form a salt, unstable for those oxides 
which catalyze adds, and breaking down to regenerate the oxide and 
forming a symmetrical ketone (837): 

(1) MO + 2R.C00H - H,0 + (R.COO)J^ - H,0 + MO + CO, 
-h R.CO.R . 

ketone 

2nd. The oxide may combine with the alcohol to form an unstable 

salt : 

MO + 2CnHto+i.0H = H,0 + M(OCnHto+i),. 

This unstable complex can decompose in two ways, either by itself 
to give the unsaturated hydrocarbon:^^ 

(2) M(0CnH2n+i)t = MO + H,0 + 2aHtn 
or with the aid of the add to form an ester: 

(3) M(OaH2n+i)t+2R .CO .OH =M0+H,0+2R .00 .OCnHto+i. 

In any case the catalytic oxide is regenerated and can continue the 
same effects. Furthermore in reaction (3), the water produced tends to 
destroy the combination, MCOCbH^b^i),, and consequently limits the for- 
mation of the ester which results from it. Since these reactions are 
very rapid, the esterification limit will be reached quickly, the cata- 
lytic oxide acting like the platinum sponge in the combination of 
iodine and hydrogen (19). 

764. We may have simultaneously formation of a ketone, produc- 
tion of imsaturated hydrocarbon (or ether), and the rapid reversible 
formation of the ester; this is what is observed when a mixture of the 
vapors of ethyl alcohol and acetic acid is passed over thoria or alumina 
heated to about 400^. 

If the conditions are such that reactions (1) and (2) do not take 
place, (3) will be the only one and we will have an advantageous 
catalytic formation of ester. 

*^ Sabatibb and Mailhb, Compl, rend.^ 150, 823 (1910). 

^ In the case of methyl alcohol, this decomposition gives methyl ether. 



766 CATALYSIS IN ORGANIC CHEMISTRY 276 

To obtain this result it is necessary to operate at such low temper- 
atures that the adds are not decomposed and that the decomposition 
into unsaturated hydrocarbon is not too rapid. 

765. Thorki which is the most active catalyst for the destruction 
of acids and which, likewise, has a powerful dehydrating effect on 
alcohols, would doubtless be less advantageous than titania, which pro- 
duces these effects less vigorously. 

766. With aromatic acids, such as benzoic and its homologs which 
have the carboxyl attached to the nucleus, thoria does not produce 
any appreciable decomposition even up to 450^ : it can be predicted 
that reaction (1) will not take place. Experiment has shown that this 
is the case and that at 350° reaction (2) is negligible as compared 
with reaction (3), which goes very rapidly. By vaporizing a saturated 
solution of benzoic add in an alcohol (there are at least 12 molecules 
of the alcohol to 1 of the acid) and passing the vapors over a train of 
thoria at 350°, there is no appreciable formation of the imsaturated 
hydrocarbon, but the benzoic acid is almost totally esterified. Methyl, 
ethyl, propyl, btUyl, ieobutyl, isoamyl and aUyl bemoatea have been 
obtained advantageously in this way. 

In spite of their greater tendency to form imsaturated hydro- 
carbons, the secondary alcohols can form benzoic esters with fairly 
good yields : this is the case with ieopropyl alcohol with which the 
formation of propylene is of minor importance. Cyclohexyl alcohol 
is more deUcate, but nevertheless gives a fairly good yield of the 
benzoate. 

Analogous results are obtained with the three ioluic adds which 
are readily esterified by thoria at 350-380°, but the practical prepara- 
tion of these esters is less advantageous on account of the smaller 
solubility of these adds, particularly the para, in the alcohols: the 
meta is the most soluble.^ 

767. Titania enables us to esterify various acids in the same man- 
ner. If a mixture of equivalent amounts of the vapors of a primary 
alcohol and an aliphatic acid, other than formic, is passed over a train 
of this oxide maintained at 280-300°, rapid esterification takes place, 
reaching a limit slightly above that observed by Berthelot and Men- 
schutldn in their experiments on direct esterification. The production 
of gas on accoimt of the destruction of the add or the alcohol is abso- 
lutely negligible. 

768. It is known that the presence of a catalyst does not change 
the location of the limit in reversible reactions, but diminishes greatly 
the time required to reach that limit. In this particular case, Berthe- 

* Sabatixb and Mailhb, Compt, rend., 153, 358 (1911). 



277 



DEHYDRATION 



770 



lot found that the limit is moved somewhat by elevation (tf the tem- 
perature. For equivalent amounts of ethyl alcohol and acetic acid, he 
found the following values of the limit: 

In the cold (10 years) 66.2% 

At 100^ (200 hours) 65.6 

170^ (42 hours) 66.6 

200** (24 hours) 67.3 

The figures show that the limit is not fixed but progresses slowly 
with the temperature and suggest a still higher value for the limit at 
280-300^ 

769. At 166^, Menschutkin found for various alcohols mixed with 
equivalent amounts of different acids, the following limits: ^ 



Acetic add 


+ methyl alcohol . 


. . . . 69.6% 


Acetic add 


+ ethyl alcohol . . , 


. . . . 66.6 


Acetic add 


+ propyl alcohol . 


. . . . 66.9 


Acetic add 


+ butyl alcohol . . . 


. . . 67.3 


Acetic add 


+ isobutyl alcohol . 


. . . . 67.4 


Propionic add 


+ isobutyl alcohol 


. . . . 68.7 


Butyric add 


+ isobutyl alcohol 


. . . . 69.6 


Isobutyric acid 


+ isobutyl alcohol 


. . . 69.6 


Sabatier and Mailhe 


obtained the following 


limits with titania at 


280-300^ 






Acetic add 


+ isobutyl alcohol 


. . . 69.5% 


Propionic add 


+ methyl alcohol . . 


. . . 72.9 


Propionic add 


+ isoamyl alcohol . . 


... 72 


But3rric add 


+ ethyl alcohol . . . 


... 71 


But3rric add 


+ isoamyl alcohol . . 


. . . 72.7 


Isobut3rric add 


+ ethyl alcohol . . . 


... 71 



These values are slightly higher than the corresponding figures 
obtained at lower temperatiu'es. 

770. Furthermore, in this rapid catalytic esterification, the same 
laws are found to hold as Berthelot formulated for direct esterification. 
An excess of (me constituent increases the amount of the other com- 
bined. Thus for 1 molecule of isobutyric add with 1, 2, and 4 mole- 
cules of ethyl alcohol, the following percentages of the add were 
esterified: 

With 1 molecule 71.0% 

2 molecules 83.5 

4 molecules 91.0 

« MxNBCBxnxiN, Aim. Ckim. Pkys. (5), ao, 280, and as, 64 (1880). 



771 CATALYSIS IN ORGANIC CHEMISTRY 278 

In the presence of more than 10 molecules of alcohol the esteri- 
fication of the add is nearly complete and, conversely^ almost all of 
the alcohol is esterified by a large excess of the add. The relative 
cost of the alcohol and acid in such cases deddes which conditions are 
most economical. 

771. Sabatier and MaOhe have prepared easily the methyl^ ethyl, 
propyl, buiyl, inobiUyl and isoamyl esters of a4xtic, propionic, buiyricj 
isobuiyric, isovaleric, caproic, pdargonic and crotonic, etc., acids. 

Benzyl alcohol gives equally good results with various adds. The 
dehydration to the resinous hydrocarbon, (CtHc),, which is effected 
so rapidly by catalytic oxides, hardly takes place at all in the presence 
of acid vapors.** 

772. Sabatier and Mailhe have found further that it is not indis- 
pensable to use as high a temperature as 280°, which is usually the 
most advantageous. 

The catalytiic activity continues, though it falls off gradually, to 
temperatures much lower where the acids and alcohols are stable. In 
this titania is superior to thoria.*^ By operating with equal molecules 
of ethyl alcohol and acetic add and passing the vapors over a 50 cm. 
train of the oxide at the rate of 0.2 molecule, or 21 g., per hour, Sa- 
batier and Mailhe obtained the following percentages of esterification: 

With ihoria With titania 

At 160° 11% ... 20% 

170° 26 . . . — 

230° 45 ... 60 

Besides, the catalytic power of titania persists almost indefinitely; 
it was not diminished by experiments on varied mixtures of alcohols 
and adds extending over 20 days. 

773. Formic acid can be esterified at these temperatures at which 
it is fairly stable. By operating with equal molecules of formic acid and 
ethyl alcohol, distributed by the same capillary tube through which 
the molecular volume passed very rapidly, in spite of this unfavorable 
circimistance, the foUowing amounts were est'Crified over titania: 

At 120° 47% 

160° 65% 

The esterification limit is nearly reached even at 150° at which 
the decomposition of formic add into gaseous products is still incon- 
siderable. 

^ Sabatibb and Mailhb, Campt. rend., 15a, 494 (1911). 

** MAQiHS and db Godon [(Butt. Soc. Chim., 39, 101 (1921)] conclude that 
ZrOi is as good as or better than TiO^. Milligan and Rbid (unpublished work) 
find silica gel to be a better esterification catalyst than dther. — £. £. R. 



279 DEHYDRATION 778 

In practice formic add, mixed with an excess of the desired alcohol, 
is passed over thoria at 150^. Methyl, ethyl, propyl, butyl, isoamyl and 
benzyl for mates have been readily prepared in this way. 

774. The comparison of these results has led Sabatier and MaQhe 
to conclude that the rapidity of the esterification of the primary alco- 
hols by the ahphatic acids, in presence of catalysts, is directly propor- 
tional to the kinetic velocities of the reacting molecules; it is as mttch 
greater as the molecules are lighter and it can be inferred that the reason 
is to be found in the greater rapidity of gaseous interchanges on the 
catalyst. 

775. The secondary alcohol, isopropyl, mixed with iscbutyric add 
does not give any evolution of propylene with titania below 300^. 
The proportion esterified was: 

At 235° 16.5% 

256° 21 

292° 37 

For primary propyl alcohol, the amount is 50 % at 235° and 72 % 
at 292°. 

776. Trimefhyl-carbinol (tertiary butyl alcohol) likewise mixed 
with i8obut3rric acid, gives 6 % ester at 235° with no formation of the 
hydrocarbon. With the isomeric primary alcohol, isobutyl, it is 22 %. 
It is only at 255° that the decomposition into butylene begins to 
manifest itself. At 265° it is quite rapid and the acidity of the mix- 
ture increases on account of the destruction of the alcohol in place of 
diminishing by esterification. 

777. These results agree well with the weakening of the alcoholic 
function in secondary and particularly in tertiary alcohols. The ve- 
locity of the catalytic esterification should be at the same time a 
fimction of the speed of the gaseous interchanges, in consequence of 
the smallness of the molecules and also of the faciUty with which the 
alcohol forms the temporary unstable complexes with the catalytic 
oxide.** 

778. BeiyUium oxide also can be employed as an esterification 
catalyst. With this oxide heated to 310°, yields of above 70 % of ester 
can be obtained. The catalyst can be regenerated by calcining at a 
red heat. With this catalyst esters of tertiary alcohols and of high 
molecular weight adds can be prepared.^ ** 

** Sabatibb and Mailhs, Compt. rend., 152, 1044 (1011). 

«' Hausbb and Klots, Chem. Zeit., 37, 146 (1013). 

^ I have tried to prepare esters by the use of beryllia and so has Dr. MnjjGAN 
but neither of ua has been able to verify the statements of Hausbb and Klotz. 
~~ £. £j. R. 



779 CATALYSIS IN ORGANIC CHEMISTRY 280 



§ 6. — ELIMINATION OF WATER BETWEEN ALCOHOLS 

AND ALDEHYDES OR KETONES 

779. The eUznination of water between alcohols and aldehydes or 
ketones can take place in several ways. The one way is to a certain 
extent comparable to eatenjicatian and leads to acetals; it can hardly 
be realised except in liquid systems. The other, more exceptional, 
gives rise to hydrocarbons and is effected in gaseous systems. 

I. — Fonnation of Acetals 

780. Aldehydes can combine directly with alcohols to give acetals: 

R.CHO + 2R^0H - H,0 + R.CH(OR0« . 

ftldehydt" aloohol Mstal 

But the direct formation is very imperfect, unless suitable ixUalysla 
are used. 

Good yields are obtained by passing for a long time a current of 
pure phosphine through a well cooled mixture of the aldehyde and 
alcohol: by this means acetaldehyde has been made to combine with 
ethyl, propyl and isobiUyl alcohols.^* 

The combination of alcohols and aldehydes is greatly aided by the 
presence of a certain amoimt of glacial acetie acid,^ 

781. Trioxymethylene, the condensation product of formaldehyde, 
readily forms methylal, HCH(OCHi)s, when it is mixed with methyl 
alcohol and heated on the water bath for 10 hoiurs with 3 % of ferric 
chloride. 

782. A good method for preparing acetals is to mix the aldehyde 
with the proper amount of alcohol containing 1 % of hydrogen chloride 
(the gas dissolved) and digest the mixture for 18 to 20 hours : the 
yields are usually satisfactory.*^ 

To obtain acetals from acetaldehyde with various aliphatic alco- 
hols, 40 g. of acetaldehyde is mixed with 60 g. of the alcohol and 1 cc. 
concentrated hydrochloric add is added and this mixture digested 24 
hours with a saturated solution of sodium chloride and 10 g. of the 
solid salt.** 

783. The action of ethyl ortho-formate on aldehydes or ketones 
readily produces their combinations with ethyl alcohol; but this re- 

* Engbl and Girabd, Jahreiib.f x88o, 694. 
** GsuTHBB, AnndUn, xa6, 62 (1863). 
B £. FiscHBB and Gibbb, BmidUe, SO, 3053 (1897). 

« Kino and Mason, EngMi patent, 101,428 of 1916, /. Soc Chem. Ind,, 35, 
1131 (1916). 



281 DEHYDRATION 784 

action does not take place without the aid of suitable catalysts. These 
may be quite varied, e.g. strong mineral acids, ferric chloridef ammo^ 
nium chloride f ethyU, dieihyU, or trieOiylramine hydrochlorides^ potassium 
bisidpliaie, ammonium sulphate or nitrate. Boiling for a few minutes 
is sufficient to assure the formation. 

Thus to prepare the aoetal from ethyl alcohol and benzaldehydef 1 
molecule of the aldehyde is mixed with 0.1 molecule ethyl ortho-form- 
ate and poured into 3 molecules of the alcohol and a little dry hy- 
drogen chloride is passed in. After ten minutes boiling, the acetal, 
CeHs . CH (OCsHb)! is obtained in 99 % yield. By using 2 g. ammo- 
niimi chloride, the yield is 97 %. 

The diethyl acetal of acetone is obtained thus with 66% yield. 

If the boiling is prolonged too greatly, the yield is more and more 
diminished, which shows that the catal3r8t tends to destroy by hydrol- 
ysis the acetal which it has formed." 

n. — Fonnation of Hydrocarbons in Gaseous System 

784. The dehydrating action of oxides such as alumina on a mix- 
ture of an alcohol and an aldehyde can eliminate all of the oxygen as 
water producing a doubly unsaturated hydrocarbon. 

This takes place when a mixture of ethyl alcohol and acetaldehyde 
is passed over the impure alumina formed by calcining ammonium 
alum. Butadiene, boiling at 2°, is obtained: 

CHjOH.CH, + OCH.CH, - 2H,0 + CH, : CH.CH : CHf 

With pure alumina, methyUallene, CHs.CH :C:CHs, is also 
formed. This reaction can be applied to the S3mthesis of rubber by 
the polymerization of the hydrocarbon obtained (213). From 100 g. 
of the mixture of aldehyde and alcohol, 25 g. of the crude hydrocarbon 
may be obtained or 16 to 18 g. of pure butadiene which may be totally 
transformed into rubber.*^ 

Similarly acetaldehyde, with isopropyl or propyl alcohols, leads to 
piperylene, CH».CH .CH.CH rCH,, boiling at 42^" 

«• Claxsbn, BeriehU, 4O9 3903 (1007). 

** OsTBOMUissLBNSxn and Kblbasinsxi, /. Russian Phyt. Chem, Soc, 47, 1500 
(1015); C. A., 10, 3170 (1016). 



CHAPTER XVII 
DEHYDRATION (Continoed) 

§ 7- — DEHYDRATION OF PHENOLS ALONE 

785. One method of preparing ethers from phenole is to distil dry 
aluminum phenylates: this works well for phenyl ether and for the 
ethers of ortho and para cresols.^ This method of preparation leads 
us to foresee that phenyl ethers can be prepared catal3rtically by the 
action of a catalytic oxide such as thoria on the vapors of the phenol 
at a suitable temperature, the mechanism of dehydration depending, 
as with the alcohols, on the formation of an unstable thorinate which 
decomposes regenerating thoria. 

We have: 2CeHj.0H + ThO, - HiO -f Th (OCeHQt 

thorinata 

and then: Th(0C«H6)i - ThO, + (CeH6)fO. 

ether 

This prediction having been verified, Sabatier and Mailhe have 
based on it an advantageoue method for the preparation of phenol ethers 
by the use of thoria.^ 

786. Simple Phenol Ethers. The vapors of the phenol are passed 
over a train of thoria kept at 400-500^. If the phenol is a liquid, it 
is introduced directly by means of the capillary tube (181) ; if it is a 
solid, its benzene solution is used. The reaction products are shaken 
with caustic soda, which extracts the unchanged phenol leaving the 
ether which is obtained entirely pure by one distillation. Phenyl ether 
can be prepared in this way very economically and in great purity 
with a yield of 50% or better; meta and para cresyl ethers can be 
readily obtained, while ethers are more difficult to obtain from orifio 
cresol and from xylenol{lfSf4)* ^^^ POor results are gotten with 
carvacroL^ 

787. Diphenylene Oxides. This method leads to the simultaneous 
formation of diphenylene oxides, fluorescent compounds, less volatile 
than the ethers, and formed by the loss of Ht. 

With ordinary phenol at 475°, there is formed along with phenyl 

1 Gladstonb and Tbibs, /. Chem. Soc., 41, 9 (1882), and 49, 25 (1886). 
' Sabati£B and Mah^hs, Compt. rend,, 151, 492 (1910). 

* Sabatisb and Mauab, BuU, Soc. Chim. (4), 11, 843 (1912). 

* Sabatubb and Mailhe, Compt. rend., 158, 608 (1914). 

282 



283 DEHYDRATION 789 

ether, boiling at 253^ and melting at 28^ a considerable amount of 

C,H4\ 
diphenylene oxide, | 0, boiling at 287^ and melting at 85^ which 

had previously been obtained by distilling calcium phenylate.* The 
cresols, xylenola, and naphthola give rise to the formation of similar 
products.* 

788. Mixed Phenol Ethers. By dehydrating over thoria, not a 
single phenol, but a mixture of two phenols, the product contains 
along with the simple ethers of the two phenols and the diphenylene 
oxides, an amount, usually* considerable, of the mixed ether derived 
from the two phenols which can be separated by careful fractionation. 
Sabatier and Mailhe have prepared the following mixed ethers, phenyU 
o.creayl, phenyl^in.creayl, phenyJrp.creayl, phenyUa-naphthyl, phenyU^ 
naphthyl, phenyUcarvacryl, p.cresylrcarvacryly as well as the phenylene- 
naphthylene oxides.' 

§ 8. — ELIMINATION OF WATER BETWEEN PHENOLS 

AND ALCOHOLS 

Synthesis of Alkyl Phenol Ethers 

789. Sabatier and Mailhe have shown that catalytic oxides such 
as thoria readily eliminate water from a phenol and an alcohol with 
the formation of a mixed ether.* This is a very advantageous method 
of preparing mixed ethers. All that is necessary is to pass a mixture 
of the phenol with an excess of the alcohol over thoria at 390-420.^ 
With methyl alcohol, which is dehydrated by thoria very slowly, the 
results are particularly good. The excess of the alcohol and most of 
the unchanged phenol are separated from the ether by fractionation. 
The remainder of the phenol is extracted by caustic soda from the 
mixed ether, which is purified by a single distillation. 

In this way, Sabatier and Mailhe have prepared the methyl ethers 
of phenol, the three cresols, xylend (1,8,4)} thymol, carvacrol, and a- 
and P-^naphthols, 

At the same time small quantities, more or less important accord- 
ing to the phenol, of the phenol ether and diphenylene oxide are ob- 
tained. A mixture of methyl alcohol and carvacrol gives methyl- 
carvacryl ether, along with dircarvacryl ether and carvacrylene^ 

* NibdebhXusbrn, BerichU, 15, 1120 (1882). 

* Sabatixb and Mailhs, Compt, rend., 151, 494 (1010). 

' Sabatibb and Mau^hb, Campt. rend,, 155, 260 (1912), and 158, 608 (1914). 

* Sabatibb and Maiiab, Compt, rend., 151, 359 (1910). 

* Sabatibb and Mahsb, Campt. rend., zsS, 608 (1914). 



790 CATALYSIS IN ORGANIC CHEMISTRY 284 

The other alcohols, in spite of their own rapid decompomtion by 
thoria, can readily give the mixed ethers : one operates around 420^ 
on phenol dissolved in excess of the alcohol, a part of which is decom- 
posed forming the unsaturated hydrocarbon. EthyU, prapyU, and 
uoamyUphenyl ethers have been prepared in this way. 

§ 9. — ELIMINATION OF WATER BETWEEN A PHENOL 

AND AN AMINE 

790. Nothing worth while is accomplished by passing a phenol and 
ammonia over a catalytic oxide at 400^ The production of amines is 
quite negligible. 

We may mention as a catalytic reaction of this sort, the action of 
a- and fi^naphthola, on aniline, the toluidinea and other aromatic 
amines, when they are heated 7 hours to about 200^ in the presence of 
1 % of iodine. The corresponding secondary amines are obtained with 
satisfactory yields." 

§ zo. — ELIMINATION OF WATER BETWEEN PHENOLS 

AND HYDROGEN SULPHIDE 

791. Sabatier and Mailhe have found that by passing the vapors 
of a phenol and hydrogen sulphide over thoria between 430 and 480^, 
the corresponding thiophenol is obtained; 

C*R*.OH + H,8 - H,0 + CASH. 

But the yield is not so good as with alcohols (744), and is not 
above 10% in the most favorable case. A temperature of 500^ de- 
creases the yield on account of the serious decomposition of the hy- 
drogen sulphide. Hence the reaction is of no practical use but is of 
only scientific interest. ^^ 

The yields are still less when other oxides are used. With phenol, 
the following yields were obtained at 450^:" 

Alumina 0.4% 

Zirconia 1.5 

Blue oxide of molybdenum 1.8 

Blue oxide of timgsten 1.5 

Chromic oxide 2.5 

Uranous oxide 3.8 

Thoria 8.0 

^* Knosyenagsl, /. prakt, Chem. (2), 89, 16 (1914). 
^^ Sabatibb and MAnsi:, Compt. rend., 150, 1220 (1910). 
» Sabatibb and Mauhb, Ccmpt. rmd., 150, 1670 (1910). 



286 DEHYDRATION 794 



§ zz.— ELIMINATION OF WATER BETWEEN PHENOLS 

AND ALDEHYDES 

792. For some years there has been prepared under the name of 
baketUey a resinous material very resistant to shock and to pressure 
and endowed with insulating properties of the first order. It results 
from the condensation of phenol or cresola with formaldehyde in the 
presence of various catalysts, chiefly substances with alkaline re- 
action." According to Baekeland,^^ who has given his name to the 
product, one of the materials, called bakelUe C, results from the re- 
action of 7 molecules of formaldehyde with 6 of phenol: 

eCAOH + 7CHiO - CisHjgOr + 6HiO. 

The formaldehyde can be replaced by meihylcdy trioxymelhylene, or 
hezafnelhylene4etram%ne. 

The products obtained are very variable according to the operating 
conditions and either liquid intermediate substances or soUds corre- 
sponding to an advanced stage of molecular condensation may be ob- 
tained. The condensation to the soUd products can be effected by 
acid catalysts such as hydrochloric acid. 

§ Z3. — FORMATION OF PHENOLIC GLUCOSIDES 

793. Quinoline employed in small proportion causes phenols to 
react with acetyUbrom-glucose forming the acetylate of the corre- 
sponding phenylrglucoside. By warmii^ for 1 hour 50 g. acetyl-brom- 
glucose with 160 g. phenol in the presence of 19 g. quinoline, the 
tetra-<u^yJrj)henyl-glucoside is obtained, the hydrolysis of which by 
baryta water separates the phenyl-glucoside.^^ 

§ Z3. — DEHYDRATION OF ALDEHYDES OR OF KETONES 

794. Frequently the presence of certain substances causes the 
condensation of two or more molecules of aldehydes or of ketones 
with the elimination of water and the formation of a single molecule 
retaining only one aldehyde or ketone group and containing double 
bonds." 

^ LxBACH, /. 8oe, Chem, Ind,, $2, 559 (1913). — Caoutchouc and Ontia-iperchaf 
X4, 9339 (1917). HunN, Ibid, i6, 9987 (1919). 
^« Babkxlakd, /. Ind. Eng. Chtm., i, 149 (1909). 
" £. FiBCHSB and von Mbchbl, Berichle, 49, 2813 (1916). 
>* Sabatixb and Maileb, Comjd, rend., iso, 1220 (1910). 



796 CATALYSIS IN ORGANIC CHEMISTRY 286 

This process is called cratonization from craUm aldehyde which is 
formed from acetaldehyde:^'' 

CH,.CHO + CH,.CHO - H,0 + CH,.CH : CH.CHO. 

Reactions of this kind can take place between molecules of dif- 
ferent aldehydes or ketones. 

Crotonization in liquid Madittm 

795. The catalysts that are able to cause the crotonization of al- 
dehydes and ketones in liquid medium are quite varied and their 
action is generally quite slow : soda, potash, hydrochloric acid, zinc 
chloride, lime, aluminum chloride and sodium acetate may be mentioned. 

In order to transform acetaldehyde into croton aldehyde, it is 
heated to 97'' for 36 hours with 20 % of its weight of a water solution 
of sodium acetate, ^^ or better to 100^ for 48 hours with a solution of 
zinc chloride.^^ 

Paraldehyde in contact with sulphuric acid also gives croton al- 
dehyde." 

The same process appUes to the crotonization of propionic aldehyde 
which can be crotonized by heating with a solution of caustic soda}^ 
The same agent is employed for butyric aldehyde.^ Dry hydrogen 
chloride^ or a solution of sodium acetate may be used to crotonize 
isobuiyric aldehyde.*^ 

Zinc chloride, or alcoholic potash, causes two or foiur molecules of 
heptaldehyds to condense.** Contact with zinc turnings is sufficient 
to crotonize isovaleric aldehyde: sodium, caustic potash and hydro- 
chloric acid produce the same effect.** 

796. Croton aldehyde itself mixed with acetaldehyde and zinc chlo- 
ride at 100^, imdergoes a second like reaction and forms hsxadienal 
(boiling at about 172°)." 

CH,.CH : CH.CHO + CH,.CHO - 

H,0 + CH,.CH : CH.CH : CH.CHO. 

^^ Sabatibb and Mailhb, Compt. rend., 150, 1570 (1910). 
^* LiBBBN, Manatsh., 13, 519 (1892). 
» MmxBB, BuU, Soc. Chim, (Z), 6, 796 (1891). 

*« DblApinb, Ann. Chim. Pkya. (8), z6, 136 (1909), and ao, 389 (1910). 
» Hoppb, Monatsh., 9, 637 (1888). 
** Raupbnstbauch, MonaUk., 8, 112 (1887). 
« (EcoNOMmto, BuU. Soc. Chim. (2), 36, 209 (1881). 
^ F088XK, Monatsh., 2, 616 (1881). 
» Pbbkin, Berichte, 1$, 2804 (1882). 

•> RiBAN, BvU. Soc. Chim. (2), 18, 64 (1872). — Kbkul^, BerichU, 3, 135 
(1870). — BoBODiN, BerichU, 6, 983 (1873). 
" KksjjlA, Annalen, i6a, 105 (1872). 



287 DEHYDRATION 799 

797. Ordinary acetone** kept for a long time in contact with 
lime,^* or aluminum chloride*^ is transformed into mssityl oxide: 

(CH,),:CH.CO.CH, 

and then into phorone: 

(CH,),C : CH . CO . CH : C (CH,)t. 

Cydoheocanone, in contact with sodium ethylate or hydrochloric 
add, condenses to an oily compound similar to mesityl oxide/^ 

^Hi.COv yCHi.CHjv 

CHj^ yC I Cf XyHt. 

NCHt.CH^^ NCHt.CH,/ 

798. Crotonization can take place in a similar manner between 
different molecules, principally between a molecule of acetone and one 
or two molecules of aldehyde. The presence of aqueous or alcoholic 
soda is most frequently efficient in causing these condensations with 
the elimination of one or two molecules of water giving compounds 
containing a ketone group and one or two double bonds. 

Benzaldehyde gives such products readily. Thus with acetone in 
prolonged contact with aqueous soda, it forms successively benzal- 
aoetone and dibenzal-aoetone:'* 

CeHj.CHO + HiCH.CO.CH, - H2O + C«H».CH :CH.CO.CH, 

and 

2CeHj.CH0 + CHs.CO.CH, - 2H2O + (C*Hj.CH : CH)»CO. 

In the presence of a Uttle soda solution, o.nitrobenzaldehyde con- 
denses with acetone to give o.niirobemalracetone:^ 

O2N.C0H4.CHO + CHs.CO.CH, - 

H,0 + 0,N.C,H4.CH : CH.CO.CH,. 

799. Benzaldehyde condenses with acetophenone in the presence of 
hydrogen chloride,'^ or of a few cubic centimeters of sodium meth- 
ylate,** to give diphenyl-propenone, CeHs . CH : CH . CO . CeH,. 

'* Pure acetone passed over heated freshly prepared alumina forms condensa- 
tion products, only about 60% of the acetone passing through unchanged. No 
gaseous products are formed. — Hoiixb Adkins. 

tt FimG» Annalen, no, 32 (1859). 

*^ LoxJiBB, Compt. rend.f 95, 602 (1882). 

^ Wallace, BeriehU, 2% 2955 (1896), C, 1897 (1), 322. 

** Claisbn and Pondbb, Annalen, 323, 139 (1884). 

** Bastsb and Dbbwbbn, BerichU, 15, 2856 (1882). 

*« Claisbn and CLAPABtos, BerichU, 14, 2463 (1881). 

w Claisbn, Beriehte, ao, 657 (1887). 



800 CATALYSIS IN ORGANIC CHEMISTRY 288 

The same aldehyde gives b«ngylid«n^ydrindone with hydrindone 
and a little alcoholic potash: 

CaHK X^Ht + OCH .CcEU — > CeH*^ X3 : CH .CaHj.** 

Cinnamic aldehyde^ digested several hours with acetophenone in 
contact with soda, passes into dipAenyl^pentodten^one:'' 

C«H«.CH:CH.CH:CH.CO.CaH». 

Cydapentanone condenses with two molecules of benzaldehyds in 
contact with soda.'* 

800. Citral (50 cc.) and acetone (65 cc.) shaken several hours with 
1 1. of 4% baryta water condense to pseudo-ianone.** 



Condensations in Gaseous Phase 

801. Catalytic dehydrating oxides can cause regular condensations 
of aldehydes or ketones in vapor phase. 

The vapors of acetcHdehyde, or of paraldehyde, passed over thoria at 
about 260^ yield, along with a mixture of methiuie and carbon mon- 
oxide resulting from the decomposition of the aldehyde, a Uquid con- 
taining water, crotanic aldehyde, hezadienal, without doubt associated 
with a certain amount of ocUUrieneal, Careful hydrogenation of the 
liquid over nickel at 180^, gives essentially a mixture of normal butyl 
and hexyl alcohols.^® 

The vapors of acetone passed over thoria at 410-20^ give consid- 
erable mesityl azide^^ 



Elimination of Water from a Single Molecule 

802. We have seen (308 and 310) that the presence of certain 
catal3rsts permits the addition of a molecule of water to certain doubly 
unsaturated hydrocarbons, the products usually being aliphatic ke- 
tones. The inverse reaction, the formation of a doubly unsaturated 
hydrocarbon by the abstraction of a molecule of water from a ketone, 
can be realized also. It has been found that the vapor of methyl- 
isopropyl-ketone, passed, under reduced pressure, over kaolin between 

•• Kipping, J. Chem. Soc., 65, 498 (1804). 
" ScHOi/rz, Beriehte, aS, 1726 (1895). 
" VobiJLndbb and Hobohm, BerichU, 2% 1840 (1896). 
*• TiXMANN And KbVgbb, BeriehU, a6, 2691 (1893). —Butt. Soc. Ckitn. (3), 9, 
798 (1893). 

^ Sabatibr and Gaudion, Compl. rend., 166, 632 (1918). 

«^ Mailhb and ds Godon, BtM, Soc. Chim. (4), ax, 63 (1917). 



289 DEHYDRATION 806 

400 and 600^, gives isoprene (which doubtless results from the is- 
omerization of 3-methyl-butadiene(l,2)).** We would have: 

CHi.CO.CH; -*H,0 + CH2:C:CC -*CH,:t;H.Cf 

NCH, \CH, \CH, 



Condensations of Aldehydes or Ketones with Various 

Organic Molecules 

803. Condensations with elimination of water comparable to cro- 
tonizations can frequently take place between aldehydes or ketones and 
molecules of various kinds, nitro compounds, phenols, esters, indols, 
pyrrols, etc. These reactions are most frequently brought about by 
the usual condensing agents, sulphuric or hydrochloric adds, zinc chlo- 
ridSf etc., or ammonia and amivsa, or anhydrous aluminum chloride. The 
products are generally unsaturated at the point where the aldehyde or 
ketone groups have disappeared. 

Thus benzaldehyde condenses with nitromethane in the presence of 
zinc chloride to give a nitro derivative of phenyl-ethylene: ** 

C.H6.CH0 + CH,N02 - H,0 + CeHe.CH : CH.NOj. 

804. The same aldehyde condenses with malonic add or its esters 
to form benzylidene-^malonic acid when heated in presence of alcoholic 
ammonia or of hydrochloric acid:^^ 

CeHfi.CHO + H,C(CO,R), - H,0 + CeHe.CH : C(C02R)t 

From equal molecules of benzaldehyde and malonic acid warmed 
1.5 hours to 55^ with an 8% alcoholic ammonia solution, a 60% yield 
of the condensed acid is obtained. The ammonia can be replaced by 
eOiyJramine or piperidine.*^ 

805. Acetone condenses with pyrrol on the addition of a few drops 
of concentrated hydrochloric add to give a crystalline product, the 
molecule of which is doubtless quadruple the formula given: 

C4H4N + CH,.CO.CH, - H,0 + C7H9N. 

« Eablx and KTBiAxmss, U, S. Patent, 1,106,290. —J. Soc, Chem. Ind., 33, 
942 (1914). 

« Pbixbs, AnndUn, 225, 321 (1884). 
** Claisbn, BerichU, 14, 348 (1881). 
^ Kmobvsmagsl Oerman patent9, 94,132, 97,735 and 164,296 (1904). 



806 CATALYSIS IN ORGANIC CHEMISTRY 290 

With 1 cc. hydrochloric acid, 14 g. pyrrol and 14 g. acetone 
dissolved in 80 cc. alcohol and heated, the yield is about 95%/* 

806. Trioxymethylene can condense with benzene or its homologs 
in presence of anhydrous aluminum chloride to give at the same time 
diphenyJ^meOiane (or a homolog) and anthracene:^' 

4C«He + (CH,0)$ - CeH5.CH,.C«H« + CiiHw + 3H,0 + Hi. 

Chlorai and bromal can react in the same way in the presence of 
anhydrous aluminum chloride on various aromatic compounds with 
the elimination of water and the loss of the aldehyde function. This 
takes place with benzene and its homologs : 

2CeH« + CCUCHO - H,0 + CCU.CHCCeH),. 

Besordne (in carbon disulphide solution) gives a similar reaction 
but with the simultaneous loss of hydrochloric acid :^^ 

2C«H4(OH), + Ca,CHO - H2O + HCl + CCl, : C[C6H,(OH),32. 

Anisol reacts with chloral to give the compound, CCUCH- 
(CeH40CH,),." 

Naphthalene, anthracene, and phenanihrene react in an analogous 
nmnner with chloral and bromal in the presence of aluminum chloride 
but with the simultaneous loss of water and halogen hydride. Thus 
naphthalene gives the compound, CClj : C (CioH7)2.'® 



§ 14. — ELIMINATION OF WATER BETWEEN ALDEHYDES 

OR EXTONES AND AMMONLA 

807. Catalytic oxides can bring about the condensation of alde- 
hydes and ammonia in various ways. 

Acetaldehyde and anunonia passed over alumina below 300^ give a 
certain amount of pyrrol by simultaneous dehydration and dehydro- 
genation:*^ 

CHs.CHO CH:CHv 

+ NH3 = 2H2O + H, + I ;nh. 

CH,.CHO CH:CH/ 

** Chelintzev and Tbunov, J, Russian Phys, Chem, Soc,, 48, 105 (1916); C. A. 
XI, 462 (1917). 
^' Frankfortbb and EoKATmrB, J. Amer, Chem, Soc., 36, 1529 (1914). 
^* Franeforter and Daniels, J, Amer. Chem, Soc. 36, 1511 (1914). 
^> Frankforter and Kritchevskt, J. Amer, Chem, Soc,, 37, 2560 (1915). 
*^ Frankforter, J, Amer, Chem, Soc,, 37, 385 (1915). 



291 DEHYDRATION 811 

Acetaldehyde and bemdldehyde carried over alumina by ammonia 
at above 300^ yield a- and y-phenylrpyridines: ^^ 

CeHj.CHO + 2CH,.CH0 + NH, - 2H, + 3H,0 + C8H4N.C«H,. 

808. Aldehydes and ammonia passed over thoria at 420-50^ give, 
by simultaneous dehydration and dehydrogenation, a considerable 
proportion of nitrilea: 

R.CHO + NH, - R.CN + H,0 + H,. 

With isovaleric aldehyde, the yield of nitrile reaches 40% and 
equally good results are obtained with isobviyriCf propionic, and even 
benzoic and anisic aldehydes.^ 

809. In contact with thoria at 300-400^, ketones and ammonia 
give ketimines. With benzophenone the yield is almost theoretical." 
We have 

R.CO.R' + NH, = H,0 + )C : NH. 

R/ 

§ 15. — ELIMINATION OF WATER BETWEEN ALDEHYDES 

AND HYDROGEN 



810. In contact with alumina below 300^, acetaldehyde condenses 
with hydrogen sulphide with simultaneous dehydration and dehydro- 
genation to give thiophene:^^ 

2CH,CH0 + H,S - H, + 2H,0 + C4H4S 

§ 16. — DEHYDRATION OF AMIDES 

811. The dehydration of amides to nitriles can be effected by ap- 
propriate catalysts. The amide mixed with the catalyst is heated to 
250-60^ for 4 hours in a flask fitted with a reflux condenser. Four 
parts by weight of catalyst are used to one of amide. ^^ 

Acetamide gave the following yields of acetonitrile: 

With alumina 68 % 

lamp black 68 

pumice 65 

powdered glass 65 

sand 52 

•^ CmcHiBABiN, J. Russian Phys, Chem, 80c., 47, 703 (1915); C. A,, % 2512 
(1915). 

■* Mailhb and db Godon, Compt. rend,, x66^ 215 (1918). 

"* MioNONNAc, Compi. rend., 169, 237 (1919). 

M BoBHNBB and Andbxws, J. Amer. Chan, 80c., 38, 2503 (1916). 



812 CATALYSIS IN ORGANIC CHEMISTRY 292 

But better 3deld8 are obtained by carrying the amide in a current 
of air over the catalyst heated to 420^, the yields being: ^* 

With pumice 91.5 

alumina 82 

sand 86.5 

graphite 75.5 

812. The same process can be applied to nascent amides furnished 
by the vapors of the acid with ammonia in excess in the presence of 
alumina or thoria at around 500^. Alumina gives the best results. 
Starting with acetic add an 85% yield of the nitrile is obtained.^* 

813. We may put along side of the catalytic dehydration of amides 
to nitriles, the action of ammonia gas on the chlorides of acids in the 
presence of catalytic oxides. The amide formed is immediately de- 
hydrated to the nitrile. 

The mixture of ammonia and the add chloride is passed over 
alumina at 490-500^ and water and hydrogen chloride are eliminated: 

R.COCl -I- NH, - R.CN + H^O + HCl. 

High yields of the nitriles are obtained in this way from propionyly 
isctnUyryl, isovalyryl and benzoyl chlorides. As the ammonia gas is 
used in excess, anunonium chloride is formed and deposits in crystals 
in a receiver placed at the end of the reaction tube.^ 

§ 17. — DEHYDRATION OF OSIMES 

814. The aldoximes which are isomeric with the amides can be 
transformed into niiriles in the same way. The vapors of the aldoximes 
are passed over alumina or (hma maintained at 350-60^ and give 
the nitriles. Isovalerald-oxime gave isovalero-nitrile and oenanthald- 
oxime gave hexyl cyanide. The ketoximss, when submitted to the 
action of these dehydration agents, undergo a complex reaction in 
which nitriles with one less carbon are formed.^' 

§ 18. — DIRECT SUIPHONATION OF AROMATIC 

COMPOUNDS 

815. The direct sulphonation of aromatic compounds by means of 
concentrated svlphuric add corresponds to the elimination of water and 
can be facilitated or modified by the presence of certain catalysts. 

» BoBHNER and Wabd, J. Amer, Chem, Soc., 38, 2505 (1916). 
" Van Epps and Ran), J. Amer. Chem, Soc., 38, 2128 (1916). 
" Mailhe, BvU. Soc. Ckim. (4), 23, 380 (1918). 
*« Mailhx and db Godon, BuU. Soc. Chim. (4), 33, 18 (1918). 



293 DEHYDRATION 817 

The addition of 1 part of iodine to 240 parts of benzene warmed 
with 584 parts sulphuric acid brings about complete sulphonation in 
5 hours; the iodine is readily recovered.** •* 

816. The catalyst most commonly employed is mercuric sulphate. 

Benzoic acid heated with sulphuric acid alone gives only the meta 
and para derivatives, but in the presence of mercuric sulphate, the 
ortho is obtained.^ 

Avihraquinone gives only the )8-monosulphonic acid with sulphuric 
acid alone, or the 2,6 and 2,7 disulphonic adds, when fuming sul- 
phuric is used. 

By heating to 130^ with 0.5 part mercury to 110 parts sulphuric 
acid and 29 parts sulphur trioxide, the a-monosulphonic add is ob- 
tained. At 160^ with 1 part mercury to 200 parts sulphuric acid and 
40 parts of the trioxide the disulphonic adds (1, 5), (1, 6), (1, 7), and 
(1, 8) are obtained." « 

Vanadium sulphaie has been proposed for aiding the sulphonation 
of pyridine.** 

§ 19. — CONDENSATIONS BT ELIMINATING MOLECULES 

OF ALCOHOLS 

• 

817. It is convenient to consider reactions in which molecules of 
aliphatic alcohols are eliminated along with those in which water is 
abstracted. Anhydrous aluminum chloride is specially suitable as a 
catalyst for such condensations. 

Ethyl ether reacts with benzene in the presence of almninum chlo- 
ride to form ethylbenzene with the elimination of alcohol:** 

CeH« + (CJH5),0 - CjHs.OH + CeHfi.CjH*. 

** HsmsMANN, English patent, 12,260 of 1915. — J. Soc. Chem. Ind,, 35, 1008 
(1916). 

*<> According to BIt and Det (J. Chem. Soc. 1x7, 1405 (1920)) iodine influences 
the sulphonation of many compounds notably that of benzoic acid, the sulphonie 
acid group taking the ortho position under the influence of iodine instead of meta 
and para: toluene, chlor- and brombenzenes are sulphonated in para position 
only instead of ortho and para. — E. E. R. 

« Ddocboth and von Schmabdel, Berichte, 40, 2411 (1907). 

« Iljikbkt, Berichte, 36, 4194 (1914). 

M In the absence of mercury salts, a very small proportion, about 3% of a 
sulphonie acid is formed along with the beta. The presence of the meroury salt 
does not seem to affect the rate of sulphonation in the beta position but increases 
the rate of sulphonation in the alpha position so enormously that the operation 
can be carried on at much lower temperatures and with weaker oleum under which 
conditions the formation of the /3-sulphonic acid is slow. — £. £. R. 

M Fabbw. v. F. Batsr & Co., German patent, 160,104. 
'Jannabch and Babtblb, Berichte, 31, 1716 (1898). 



818 CATALYSIS IN ORGANIC CHEMISTRY 294 

818. Under the same conditions benzene reacts with the chlor- 
methyl ethers by the elimination of alcohol to form benzyl chloride along 
with some of the ether C«H«.CHj.O.R(889). We have:*« 

C«H« + ClCHi.O.R - ROH + CeH6.CH,Cl, 

alcohol 

819. Ethyl nitrate with benzene and aluminum chloride, gives a 
vigorous reaction which leads to nitrobenzene and the separation of 
alcohol :•' 

CaHe + 0,N.O.C2H6 - CeEU.NQj + C»H».OH. 

** SoBOiBLBT, Compl, rend. J 157, 1443 (1913). 
•' BoBDTKBB, BvU. Soc. Ckim. (4), 3, 726 (1908). 



CHAPTER XVIII 

DECOMPOSITION OF ACIDS 

820. The aliphatic acids are very stable under the action of heat, 
except formiCy which is decomposed by heat under many conditions. 
We will take up separately the catalytic decomposition of formic add 
and then the decomposition of other aliphatic and aromatic acids 
under the influence of metals and of oxides. The action of the oxides 
leads to important applications which will be studied in succession, the 
preparation of symmetrical ketones, of mixed ketones and of aldehydes, 

DECOMPOSITION OF FORMIC ACID 

821. The decomposition of formic acid by heat may go in several 
distinct directions, either by the separation of carbon dioxide: 

H.CCH-COj + H, (1) 

or by the elimination of waJler: 

H.COjH-CO + HaO (2) 

or by the simultaneous elimination of water and carbon dioxide from 
two molecules: 

2H . COJH - H.CO.H + Cd + H«0. (3) 

formaldehyde 

If reactions (1) and (3) coexist, the nascent hydrogen from (1) 
may sometimes act on the formaldehyde produced in (3) to trans- 
form it into methyl alcohol. We will then have : 

3H .CO.H - CH, .OH + 2C0j + HjO. (4) 

The presence of a given catalyst will have the effect of turning 
the decomposition either into one of these directions or into several 
at the same time, by lowering more or less the temperature of the 
decomposition. 

^ Bbbthelot, Ann, Ckim. Phya, (4), z8, 42 (1869). — Saintb-Claibs-Devillb 
and Debrat, Compi. rend., 78, 1782 (1874). — Blacxaddbb, Zeit. phys, Chem,, 
8z, 386 (1912). 

296 



822 CATALYSIS IN ORGANIC CHEMISTRY 296 

822. Reaction (1) which is a dehydrogenation, Is produced at 
the ordinary temperature by rhodium black,^ or by paUadium black* 

Reaction (2) which is a dehydration is brought about by sub- 
stances that take up water, sidphuric acid which acts below 100^, dry 
oxalic acid above 105^ or anhydrous sodium and potassium formales 
above 150''.» 

823. Sabatier and Mailhe have studied the decomposition of for- 
mic acid under the influence of various catalysts, including finely 
divided metals, anhydrous oxides and some other substances.^ Com- 
parisons have been made under analogous experimental conditions, 
the addition of the formic add being at about 0.27 g. per minute and 
the pulverulent solid catal3rst forming a layer SO cm. long in a hor- 
izontal Jena glass tube heated to a known temperature. 

The tube without catalyst gave a negligible decomposition below 
300^9 while at 340^ 2.6 cc. of gas was collected per minute, chiefly a 
mixture of hydrogen and carbon dioxide (reaction 1) with a few per- 
cent of carbon monoxide (reaction 2). 

824. The catalysts studied can be divided into three groups : 
1st. Dehydrogenating Cataljrsts. These are the ones that cause re- 
action (1) ahnost exclusively, doubtless because they give rise to a 
temporary compound with one of the products, either hydrogen or 
carbon dioxide. The metals doubtless combine with the hydrogen: 

PaUadium (sponge) acts at 110^ and produces total decomposi- 
tion at 245^. 

PlaJtinum (sponge) begins to decompose it at 120^, the reaction 
being complete at 215^. 

Reduced copper (light violet) evolves at 190^ 278 cc. of gas 
containing equal amounts of hydrogen and carbon dioxide. 

Reduced nickel at 280^ disengages 290 cc. gas containing only 
traces of carbon monoxide. 

Finely divided cadmium, prepared by reducing the oxide, gives 
325 cc. gas per minute at 280^. 

Stannous oxide begins to act above 150^, while at 285^ it evolves 
172 cc. of gas, being slowly reduced to small globules of tin which con- 
tinue the catalysis. The gas contains a small excess of carbon dioxide 
due to reaction (3) which takes place to a slight extent. 

An analogous result is produced by zinc oxide where the temporary 
production of zinc carbonate is doubtless the cause of the reaction : 
it begins to act at about 190^ and at 230^ disengages 172 cc. of gas 
containing 51 % of carbon dioxide and 49 % of hydrogen by voliune. 

* Zblinskt and Glinka, BerichJU, 44, 2305 (1911). 

* LoBiN, Campi, rend., 8a, 750 and BvU 80c, Chim. (2), 35, 517 (1876). 

* Sabatobb and Maileb, Compi. rend,, 15a, 1212 (1911). 



297 DECOMPOSITION OF ACIDS 826 

The production of formaldshyde according to equation (3) amounts to 
2%.* At 245° this may be raised to 12% of formaldehyde.* 

825. 2nd. Dehydrating Catalysts. Reaction (2) takes place ex- 
clusively with titania above 170^, and at 320^ 180 cc. of practically 
pure carbon monoxide is collected per minute. 

The blue oxide of tungsten (715) acts the same way : at 270^ it 
gives 195 cc. carbon monoxide practically pure. 

The reaction goes in the same direction, but with reaction (3) as a 
side reaction to a slight extent, that is formaldehyde is produced 
equivalent to the carbon dioxide without hydrogen, with alumina, 
eilica, zirconia, and uranouH oxide, UOt. 

With alumina; the decomposition, which begins at about 234^, 
yields carbon monoxide containing 6% of the dioxide. Reaction (2) 
dominates but about 10% is decomposed according to (3) giving 
formaldehyde. 

At 340^ the disengagement of gas reaches 192 cc. per minute, but 
the gas then contains a little hydrogen resulting from the partial 
decomposition of the formaldehyde. 

Silica, which is less active than alumina, gives about 3% of 
reaction (3). 

At 340^, zirconia gives 144 cc. gas containing 5% of carbon 
dioxide: reaction (3) takes place to an extent of 10%. 

With uranous oxide, reaction (3) is almost as important as (2). 

826. 3rd. Mixed Catalysts. These are the most niunerous of all. 
They produce reactions (1) and (2) simultaneously, usually with (3) 
as a minor side reaction. 

This is what takes place with tharia. The decomposition shown by 
a slight evolution of gas, begins around 230.^ It is still quite slow at 
250^, and gives a gas which contains 75 % carbon monoxide, 15 % car- 
bon dioxide, and 10 % hydrogen; the condensed liquid contains formal- 
dehyde. These figures show that of 100 molecules of formic add, 79 
undergo reaction (2), the other 21 being equally divided between (1) 
and (3). 

Elevation of temperature modifies the conditions of the decompo- 
sition which is more and more rapid. At 320^ the gas amounts to 
120 cc. per minute and the carbon dioxide reaches 45 % and the liquid 
contains considerable methyl alcohol, resulting from the intervention of 
reaction (4) which may be regarded as a reduction of formic add by 
formaldehyde: 

H.COiH + H.CO.H - COf + CHi.OH. 

* Sabatibb and Mjjuhm, Compi, rend., 1^2, 1212 (1011). 

• HoncANM and Schibstbd, BerichU, 5i» 1398 (1018). 



827 CATALYSIS IN ORGANIC CHEMISTRY 298 

The amount of methyl alcohol increases above 350^ and as formalde- 
hyde is then partially decomposed into carbon monoxide and hydro- 
gen, the proportion of hydrogen increases while that of carbon dioxide 
decreases. At 375^, the gas is 144 cc. per minute containing only 33 % 
carbon dioxide. The condensate contains methyl alcohol. 

827. For certain mixed catalysts, reaction (1) predominates; this 
is the case with the blue oxide of molybdenum^ MosOs, resulting from 
the reduction of molybdic oxide by the formic acid at 340^. The de- 
composition, already clean at 105^, gives at 340^, 325 cc. of gas con- 
taining only 5% carbon monoxide. Of 12 molecules of the acid, 9 
decompose according to reaction (1), 2 according to (3) and 1 ac- 
cording to (2). 

Ferrous oxide, an active catalyst, and lime and broken Jena glass, 
mediocre catalysts, favor reaction (1) decidedly. 

828. The two reactions (1) and (2) are of about equal importance 
with powdered white glass which acts at 240^. 

The dehydration reaction (2) predominates as is indicated by the 
proportion of carbon dioxide being less than 33 %, with a large niunber 
of substances whose absolute activities differ greatly, thus: 

Powdered pimiice liberates at 340^ . . 4 cc. per minute. 

Magnesia 10 

Charcoal from light wood 95 

light chromic oxide 150 

Black vanadiimi oxide 215 

Manganous oxide 225 

Beryllium oxide 250 

Reaction (3) takes place more or less with all of these. 

DECOMPOSITION OF MONOBASIC ORGANIC ACIDS 

829. In the action of heat on monobasic organic acids we find the 
three types of reactions given above for formic acid (821), namely: 

1st. Elimination of carbon dioxide: 

R .00, OH - CO, + RH (1) 

hydrooarbon 

2nd. Separation of water alone, which can take place with primary 
or secondaxy adds only: 

RR'.CH.CO.OH - H,0 + RR^C : CO (2) 

ketene 

3rd. Simultaneous elimination of water and carbon dioxide from 
two molecules of acid, giving a symmetrical ketone: 



299 DECOMPOSITION OF ACIDS 831 

2R .CO .OH - COi + HiO + R.CO.R (3) 

ketone 

Reaction (2) is realised only exceptionally, as in the case of the ac- 
tion of an incandescent platinum spiral on the vapors, not of acetic 
add but of ace/tanhydride, giving the ketene, CH:CO/ because the 
ketenes that are formed are very unstable and tend to polymerize 
ending up with carbonaceous substances. 

Reactions (1) and (3) are of great importance. 

830. Without the aid of a cataljrst these two reactions take place 
simultaneously at a dull red heat: but the hydrocarbon and even the 
ketone are more or less destroyed and a complex pyrogenetic mixture 
results. The presence of a cataljrst, either a finely divided metal or an 
oxide, orients the reaction and lowers the reaction temperature. 

With aliphatic acids, reaction (1) is the most difficult to effect and 
is obtained only with difficulty by the use of finely divided metals. 
On the contrary, reaction (3) is easily brought about by the aid of 
oxide catalysts and leads to a practical method for the preparation of 
symmetrical ketones. 

AronuUic and cyclic acids frequently give reaction (1) under the 
action of heat alone so that the aid of catal3rsts is often superfluous* 
However, the presence of suitably chosen catalysts can either accelerate 
reaction (1) or substitute for it, partially or entirely, reaction (3) 
which would not take place in their absence. But among the aro- 
matic adds it is necessary to distinguish between those in which the 
carboxyl is joined directly to the nucleus and those in which the car- 
boxyl is in a side chain. For the latter, e.g. phenylnicetic add, C«Hs. « 
CHs.COOH, reaction (3) is easily realized by the aid of cataljrtic 
oxides as is the case with aliphatic acids. 

For the former, e.g. benzoic, CeHs.COOH, and the toluic adds, re- 
aistion (1) is the one that alwa3rs tends to take place, reaction (3) 
being very difficult to obtain, at least with the aromatic adds alone. 

SIMPLE ELIMINATION OF CARBON DIOXIDE 

831. In the case of aliphatic acids this is accomplished more or less 
by finely divided metals. 

Finely divided copper commences to decompose the vapors of acetic 
acid at 260^, and an evolution of gas is obtained, slow at first but 
quite regular at 390-410^, containing 7 volmnes of carbon dioxide to 1 of 
methane. The formation of some acetone is observed. Reactions (1) 
and (3) are catalyzed and the composition of the gas shows that of 13 

' WnACOBB, J. Chem. Soc., 91, 1038 (1001). 



882 CATALYSIS IN ORGANIC CHEMISTRY 300 

molecules of the addi 1 has decomposed according to reaction (1) and 
12 have given acetone. 

832. Reduced nickel causes^ slowly below 240^, rapidly above 320^, 
an analogous decomposition. The gas contains 50% of methane and 
reaction (1) seems to have taken place exclusively, but a portion of 
the adds is decomposed into carbonaceous substances which are de- 
posited on the metal.* 

833. Other aliphatic adds give analogous results. The action of 
copper is slow. That of nkkd is much more rapid: at 230^, propionic 
acid is broken down into carbon dioxide and ethane which is largely 
decomposed into methane, carbon and hydrogen. No ketone is 
formed, but a part of the add is reduced to the aldehyde. At 250^, 
butyric acid gives analogous results, so do iedbutyric and eaproic.* 

834. With aromatic acide the decomposition into carbon dioxide 
and hydrocarbon is usually quite easy. 

The vapors of benssoic acid carried along by carbon dioxide over 
reduced copper at 550^, are totally decomposed into benzene and car- 
bon dioxide. 

Over nickel, or over the oxide which is rapidly reduced at that 
temperature, the bensene produced is almost entirely broken up with 
the depodtion of carbon and the liberation of hydrogen and methane. 
Under the same conditions, reduced iron gives benzene, which is par- 
tially destroyed, and some diphenyl.^^ 

835. In contact with copper powder, coumanic acid is regularly 
transformed into y-pyrone:^^ 

CO CO 

/ \ / \ 

HC CH HC CH 

— ► • • + COt. 

HC C.COOH HC CH 

o o 

836. The presence of alkaloids favors the decompodtion of the 
carboxy-campAor acids at 70^ into camphor and carbon dioxide. With 
an inactive alkaloid, in polarized light, the dextro and laevo adds are 
decomposed at the same rate; with an active alkaloid, the velodties 
are different. Thus with quinine a difference of 46% is found." 

The conditions of this decompodtion in the presence of quinoline, 

* Sabatobb and Sbndbkbnb, Ann, Chitn, Phys, (8), 4, 467 (1905). 

• MAHiHB, BvU, Soc. Chim. (4), 5, 616 (1909). 

^* Sabatubb and MAUiHB, Convpt, rend,, 159, 217 (1914). 
u WnxsrJLTTEB and PuiofBBBB, Berichte, 38, 1461 (1908). 
u Fajanb, ZeU. phyHk. Chem., 73, 25 (1910). 



301 DECX>MPOSrnON OF ACIDS 889 

pyridine, piperidine, and of other amines, bensyl-amine, allyl-, iso- 
amyl-amine, etc., have been studied in detail, in various solvents at 80^ 
witli the result that the formation of a complex by the add and the 
amine appears to be the cause of the catalysis in every case.^ 

SIMULTANEOUS ELIMINATION OF WATER AND 

CARBON DIOXIDE 

L Preparation of Symmetrical Ketones 

837. This is the reaction that is specially catalysed by metallic 
oxides. 

It is derived in fact from the old method of preparing symmetrical 
ketones by calcining at a red heat the calcium or barium salts of mon- 
obasic organic acids: 

(R.COi)«Ba - R.CO.R + BaCOt. 

Squibb conceived the idea of transforming this reaction into a cat- 
alytic one. By passing the vapors of acetic acid over barium carbonaie 
heated to about 500^, a regular and continuous decomposition of the 
acetic acids into acetone, water and carbon dioxide is obtained: 

2CH,.C0JH - CH,.CO.CH, + COt + HA 

The process which gives a yield of better than 90 % has been used 
industrially. The carbonates of all the metals whose acetates give 
acetone on calcination may be used.^^ We have studied above (161) 
the mechanism of this reaction* 

838. Ipatief described an analogous formation when he used sine 
oxide or carbonate or the carbonates of calcium, barium and strontium. 
Acetic add gives acetone, and propionic add, dieihyJrketone.^* 

839. Caldom Carbonate. This is an excellent catalyst for acetic 
add, a short column at 450^ is sufficient to transform the add com- 
pletely into practically pure acetone with the evolution of nothing but 
carbon dioxide and water. 

With propionic acid, the yield of diethylrketone is very satisfactory, 
some propionic aldehyde is obtained and the gas contains a httle eth' 
ylene. This formation of the aldehyde increases with the complexity of 
the molecule and appears to be correlative to the production of the 
unsaturated hydrocarbon. We have: 

CaHja+iCO.OH » CnHto + H.CO.OH. 

bydrooftrbon fonnioaoid 

» Bbbdio and Jotnxb, ZeU. f. Elektroehem., 34, 286 (1018). 
M SquniB, J. Amer. Chem. Soe., 17, 187 (1896), and 18, 231 (1896). — Gonbot, 
Be9. g^. Sd., 139 663 (1902). 

^ Ipatisf and Schitlmaiin, J. Russian Phys. Chem. Soe., 369 764 (1904). 



MO CATALYSIS IN ORGANIC CHEMISTRY 302 

The f onnic add thus produced can break up at once into CDs + Hs 
or into CO + HsO (821), but it can act also on the add that is being 
used reducing it to the aldehyde (851). 

The secondary reactions, still more important for butyric acid, are 
exaggerated with ieobviyric and isovaleric adds. 

The calcium carbonate used is blackened by the decomposition of a 
small portion of the acid, but nevertheless conserves its catalytic activ- 
ity almost indefinitely and remains as carbonate for the most part.^* 

Benzoic acid is scarcely attacked till about 550^, and gives chiefly 
benzene and carbon dioxide with only a little benzophenone and traces 
of anihraquinone.^'' 

The same difBiculty is encountered with the t3rpical aromatic adds 
in which the carboxyl is united directly to the nucleus, such as ortho, 
meta, and paraioluic acids and the naphthoic acids. 

On the contrary, aromatic adds in which the carbo^^l is in a side 
chain, such as phenylrocetic, and phenyJrpropionic adds can be advan* 
tageously transformed into the corresponding symmetrical ketones at 
430-70^ 

840. Among the metallic oxides the most suitable for the produc- 
tion of ketones are thoria and manganous oxide. It is suffident to pass 
the vapors of the add over a layer of the oxide, usually below 450^. 

Alumina. Alumina gives very good results with aceHc^ not quite 
so good with propionic and quite poor with isdbuJtyric.^^ With benzoic 
only a slow decompodtion into benzene is effected. 

Chromic Oxide. The results are analogous to those obtained with 
aliunina. 

Uranium and Zirconium Oxides. These give nearly the same re- 
sults but their activity diminishes quite rapidly. 

Lime. Lime acts as the carbonate. When it is used at 400^, it is 
possible to observe the formation of the intermediate salt, the decom- 
position of which furnishes the ketone and which is decomposed only 
above 420^ for the a4i^aie and 460^ for the buJlyrais. The temperatures 
reached can account for some decompodtion of the ketones formed. 

841. Zinc Oxide. With zinc oxide, the ojcetaJLe is decomposed above 
280° and very rapidly at 340° ; the production of acetone is therefore 
very easy. The difficulty of forming the ketone increases with the 
molecular weight of the acid and is partly due to the volatility of the 
zinc salt. Benzoic add is not attacked below 500° and then gives only 
benzene. 

^* Sabatosr and MAUiHB, BvU. Sac. Chim, (4), 13, 319 (1913) and Compt. rend,, 
156, 1730 (1913). 

^^ SABATncR and Mailhb, CompL rend., 159, 217 (1914). 
» Sbndbbxnb, BvU. 80c. Chim. (4), 3i 824 (1908). 



303 DECOMPOSITION OF ACIDS 841 

842. Cadmium Oxide. This is slowly reduced by the acid vapors 
but without the activity being diminished by the formation of the 
metal which can be seen sublimed in the tube. At 400-450^ it can 
readily transform acetic, propionic, butyric and valeric adds into their 
symmetrical ketones; the results are not so good with branched chain 
acids as iscbiUyric and isovaleric, with which the gas evolved is no 
longer pure carbon dioxide but contains considerable amounts of the 
unsaturated hydrocarbons, carbon monoxide and hydrogen.^* 

It acts at 450^, and violently at 500^, on the vapors of benzoic acid 
to give benzene, the reduction of the oxide hardly modifying the 
catal3rsis.** 

843. Oxides of Iron. Ferroue oxide resulting from the calcination 
of the oxalate as well as ferric oxide which is rapidly reduced to the 
ferrous, can give good results with aliphatic acids at 450-90^. The 
yield of ketone is excellent with acetic or propionic, good with caprylic 
and poor with iscbutyric or isovaleric add.*^ 

The immediate formation of a ferrous compound is the basis of a 
process for the preparation of ketones by heating an acid with 10% 
of its weight of iron scale : this works well for the higher fatty acids 
from lauric up to melissic. Thus stearic add gives 80 % of the ketone. 
The results are not so good with oleic, elaldic, and brassidic and are 
poor with the lower acids, acetic, butyric, etc., as well as with phenyl- 
acetic, benzoic, suberic, and sebadc,^ 

With benzoic acid at 550^, ferric oxide acts like iron (834), but its 
simultaneous reduction causes the formation of a certain amount of 
phenol which results from the oxidation of the benzene formed.^ 

844. Thoria. Thoria of which the valuable qualities of constant 
activity and ready revivification have been mentioned in connection 
with the dehydration of alcohols (708), gives excellent results with 
various monobasic aliphatic acids and enables us to prepare with good 
yields, acetone, diethylrketone, dipropyl-4zetone, diisopropyUketone, diiso- 
biUyl'kei(me, dibutyUketone, etc., as well as ketones derived from aro- 
matic acids in which the carboxyl is not joined immediately to the 
nucleus, such as phenylrocetic, fi^henyUpropionic, etc.** 

Benzoic acid is only slowly attacked by thoria even at 550^ and 
then is only decomposed into benzene and carbon dioxide.** 

» Mah^hs, BvU. See. Chim. (4), 13, 666 (1913). 

** Sabatibb and Mah^hs, Compt. rend,, 159, 217 (1914). 

^ Mailhs, Compt. rend,, 157, 219 (1913). 

** Eastbbfibld and Tatlor, /. Chem, 80c,, 99, 2298 (1911). 

" Sabatibb and Mah^hb, Compt, rend,, 159, 217 (1914). 

^ Sbndbbxns, Ann. Chim. Phys. (8), 18, 243 (1913). 

* Sabatibb and Mailbb, Compt. rend., 159, 217 (1914). 



846 CATALYSIS IN ORGANIC CHEMISTRY 304 

845. Manganotts Oxide. This oxide prepared by calcining the 
precipitated carbonate in the vapor of methyl alcohol, is on account of 
its low price and its great activityi very useful for the preparation of 
ketones at 400-450^. The carbonaceous deposits do little harm and 
the same lot of oxide has been used in 22 different preparations. In 
the case of slightly volatile acids, carbon dioxide is used to carry their 
vapors along. 

The yields of symmetrical ketones are very high, not only for ace- 
tic, propionic and valeric adds, but also for isobutyric, with which an 
experiment carried out at 400-410^ gave a 70% yield, with caproic, 
heptoic, rumylic as well as with phenylrocetic. l^th benzoic acid at 550^ 
a little benzophenone is formed; but chiefly herncne}^ 

846. Lithium Carbonate. At 550^ this is the most advantageous 
catalyst for transforming benzoic acid into benzophenone, always ac- 
companied by a little anthraquinone; but even in this, the most 
favorable case, much benzene is formed.^ 

847. Formation of Ketones in Liquid Medium. In the case of 
monobasic acids which boil above 300^, the ketones can be formed by 
heating the acids somewhat above 300^ with various catalysts, includ- 
ing the oxides mentioned above, silica, silicates and also finely divided 
metals. Stearic add yields stearone in 3 hours.^ 

n. Preparation of Mixed Ketones 

848. A long time ago Williamson showed that the calcination of a 
mixture of the calcium salts of two fatty acids gave the mixed 
ketone:" 

(R.CO0«Ca + (R'.CO,),Ca - 2CaC0, + 2R.C0.R'. 

It might be expected that the catalytic decomposition by means of 
oxides when applied, not to a single acid but to a mixture of two acids, 
would give the mixed ketone derived from the two acids instead of the 
symmetrical ketone. Senderens found this to be the case. We have: 

R.COjH + R'.CO»H - C0» + H»0 + R.CO.R'. 

A simple method of preparing mixed ketones is to pass a mixture 
of the vapofs of the two acids over thoria at about 400°. 

For the success of this method it is sufficient that one of the adds 
is catalyzed by thoria: we may use two aliphatic adds or one ali- 
phatic with benzoic or a toluic acid, but not benzoic with a toluic. 

** Sabatubb and Mah^hs, Compt. rend., 158, 830 (1914). 
*' ScmcHT Act. Gbs. and GnUv, Oerman patents, 295,657 and 296,677. — /. 
Soe. Chem. Ind., 36, 569 and 615 (1917). 
** WnjJAMSON, Annalen, 8z, 86 (1852). 



306 DECOMPOSITION OF ACIDS 861 

The chief reaction is usually that which furnishes the mixed ke- 
tone, but it is always accompanied by the reactions that the two adds 
would undergo separately. We obtain three ketones if we start with 
two aliphatic adds or an aliphatic and phenyl acetic, but only two 
when an aliphatic acid is used with benzoic, a toluic, or a naphthoic. 

The separation of the ketones is easily accomplished by fractiona- 
tion. Numerous mixed ketones have been prepared in this way. 

849. The green oxide of uranium, though less active, can replace 
thoria for this preparation: zirconia acts in the same way, but does 
not give as good results with the homologs of benzoic add. lAme, 
zinc oxide, alumina, and chromic oxide produce acetophenone easily but 
give poorer and poorer results as the aliphatic add increases in molec- 
ular wdght. 

Titania, stannic oxide and ceria give decomposition products 
chiefly.*^ 

Cadmium oxide, ferrous and ferric oorides,^^ and calcium carbonate 
are excellent catalysts for mixed ketones.'^ 

850. Manganotts oxide at 400-450^ is as good as thoria and by its 
use mixed ketones have been prepared from benzoic add with lavric, 
myristic, CiiHnOs, and stearic, CiJImOs, as well as phenylracetic.'^ 



CATALYTIC PREPARATION OF ALDEHYDES 

851. If in Williamson's method for preparing mixed ketones, one 
of the caldum salts is a formate, an aldehyde** is produced accom- 
panied by the decomposition products of the individual salts, the 
symmetrical ketone, R.CO.R, formaldehyde, and methyl alcohol as well 
as gaseous products from the formate: 

(R.C0j)2Ca + (H.COOiCa - 2CaC0, + 2R CO.H 

Analogies would lead us to expect that a mixture of the vapors of 
formic add and another monobasic organic add passed over an oxide 
catalyst would give the aldehyde corresponding to that acid according 
to the reaction: 

R.COiH + H.COiH - R.CO.H + CO, + H,0. 

** SlNDIBSKS, LOC. Cit. 

** Maiiab, Compt. rend,, 157, 219 (1913). 
*^ Sabatisb and Mailhx, Cempt, rend,, 156, 1732 (1913). 
" Sabatibb and Mailhb, Compt. rend,, 158, 830 (1914). 
" LncpMCHT, Annalen, 97, 308 (1866). — - Pibia, Ann, Chim, Phya, (3), 489 118 
(1856). 



862 CATALYSIS IN ORGANIC CHEMISTRY 306 

852. Sabatier and Mailhe were able to realize this reaction with 
Htania as a catalyst. This constitutes a general method for the prep- 
aration of aldehydes from acids. It is sufficient to pass the vapors 
of the acid mixed with an excess for formic acid over titania heated 
to 300^. There is evolved a mixture of carbon monoxide resulting 
from the decomposition of the formic acid by the titania (825) and 
carbon dioxide from the desired reaction. The condensate is a mixture 
of water, aldehyde, and unchanged acids from which the aldehyde is 
easily separated. 

Aldehydes derived from various aliphatic adds up to C9 have been 
thus prepared with yields above 40% and reaching 90%. 

Thus fumylic, or pelargonic acid, gives 85% of nonylic aldehyde. 
Usually no ketone is formed; only very small amounts of the ketones 
are formed with acids containing more than 5 carbon atoms. 

The unsaturated add, crotanic, is likewise transformed into the 
aldehyde. The reaction gives poor results with benzoic add but works 
well with phenyl-acetic, the constitution of which is more like the 
aliphatic acids. It gives a 70 % yield.*^ 

853. Manganous oxide can be substituted for titania and has the 
advantages of being readily prepared and of retaining its activity be- 
cause it gives rise to less tarry deposits. The operation should be 
conducted at a little higher temperature, 300-350^. The yields are very 
satisfactory, reaching 50% with isovaleric acid, Caproic, heptoic, 
octoic, and nonylic aldehydes have been prepared in this way.'* 

854. The use of thoria is less advantageous because it requires a 
higher temperature and because it favors the formation of ketones 
which are found with the aldehydes; however, by operating at 270- 
300^, 25 to 30 %, and sometimes more, of the aldehydes are obtained.'^ 



DECOMPOSITION OF DIBASIC ACIDS 

855. Solid oxalic add, HOOC.COOH, mixed with alimiina is de- 
composed below 100^ into water, carbon monoxide and dioxide.'* 

Glycerine mixed with crystallized oxalic add produces a different 
result: at 100-110^ carbon dioxide and formic add are produced: 

HOOC.COOH - CO, + H.CO,H. 

When the reaction dies down all that is necessary to start it again 
is to add some more oxalic acid and so on, the glycerine being able to 

** Sabatcdb and Mailhb, Compl. rend., 154, 561 (1912). 
** Sabatier and Mailbb, Campt. rend., 158, 985 (1914). 
*• Sbndbbbns, BuU. 80c. Chim. (4), 3, 828 (1908). 



307 DECOMPOSITION OP ACIDS 867 

serve almost indefinitely, and hence playing the part of a catal3rst. 
In reality there is first the production of a glycerine marKhazaUUe: 

HOH,C.CH(OH).CH,OH + HOOC.COOH - 
H,0 + HGHjC . CH (OH) . CH, . CO, . COOH. 

At 100-110^ this ester loses water and gives the monoformine, 
HOHsC.CH(OH).CHs.CO,H, which is saponified by the water set 
free in the first reaction Uberating formic add and glycerine which is 
thus free to recommence the process. 

856. The use of mangamma oxide permits the preparation of cycUh 
perUanones from €rdibasic fatly acids. 

The vapors of adipic acid carried along by a current of carbon 
dioxide over manganous oxide at 350^, give an 85% yield of cydo' 
perUarume: 

CH, . CH, . COaH CH, . CH,v 

= CO, + H,0 + . )C0. 

CH,.CH,.CO,H CH,.CH,/ 

Likewise fi^meihylrcyclaperUanane is prepared from P-methyUadipic 
acidy 

But with Bvheric acid, in which the carboxyl groups are separated 
by 6 carbon atoms, the process gives only a poor yield of siuberone and 
tarry substances are formed which gum up the catalyst.'' 

CATALYTIC DBCOMPOSmON OF ACID ANHYDRIDES 

857. The anhydrides like the acids can be decomposed catal3rt- 
ically to form the corresponding symmetrical ketanee, carbon dioxide 
only being eliminated: 

R.CO.O.CO.R - CO, + R.CO.R. 

Precipitated calcium carbonate gives good results at 450-500^ with 
the anhydrides of acetic, propionic, isovaleric, etc., acids. Thoria is also 
suitable for this reaction. 

This process gives a mixed ketone along with the two symmetrical 
ketones when an acid and the anhydride of another acid are used 
together.*' 

*' Sabatqbb and Maxlhm, Campt. rend., 158, 085 (1914). 
** GoDCHOT and Tabottbt, BuU, 80c. Chim. (4), 2$, 352 (1919). 
'* Sabatixr and Mailhx, BuU. 8oe. Chim. (4), 13, 320 (1913), and Ccmpt. rend., 
156, 1733 (1913). 



CHAPTER XIX 
DECOMPOSmON OF ESTERS OF ORGANIC ACIDS 

S I. — ESTERS OF MONOBASIC ACIDS 

858. In the absence of catalysts the esters of monobasic acids are 
difficult to decompose by simply heating; the decomposition is slow 
and such high temperatures are required that the molecules are broken 
up. We may mention that ethyl bemoate heated in a sealed tube above 
300^ is slowly decomposed into bensoic acid and ethylene. Colson, 
who noted this reaction and a similar decomposition of ethyl stecaraie, 
considered this tendency to decompose into the acid and an unsatu- 
rated hydrocarbon a general property of esters.^ 

The presence of a catalyst acting at the same time on the alcohols 
and on the acids should greatly facilitate the decomposition of esters 
which should yield, in conformity with what has been said abovei the 
unsaturated hydrocarbon and the decomposition products of the acid, 
water, carbon dioxide, and the symmetrical ketone. Some observa- 
tions relative to the action of alumina on ethyl acetate, propionate 
and butyrate confirmed this prediction, but on the contrary, these 
same esters gave with thoria a complicated decomposition which has 
not been cleared up.* 

Sabatier and Mailhe have studied a great number of cases of the 
action of various catalytic oxides on esters of various sorts and have 
indicated the general conditions that govern the decomposition.' 

Formic esters require separate treatment and will be taken up 
after the other esters. 

859. If an ester derived from a primary aliphatic alcohol and from 
a monobasic organic acid, other than formic, be brought in contact 
with a catalytic oxide, MO, derived from an amphoteric hydroxide, 
M(OH)s, the following reaction will take place: 

2R.C0.0CnH,n+i + 2M0 « (R.COO)iM + (CaH„^iO)JVl. 



The salt, (RCO.O)sM, and the alcohol derivative, (CnH2n+iO)iM 
are both unstable, if the oxide chosen is at the same time a catalyst 

> GoLSON, C<mpt. rend., 147, 1054 (1008). 

* Sbndbbbns, BtiZZ. Soe. Chim. (4), 5, 482 (1909). 

* Sabatieb and Mailbb, Campt, rend., 15a, 669 (1912), and 154, 49 and 176 
(1912). 

808 



309 DECOMPOSITION OF ESTERS OF ORGANIC ACIDS 861 

for the decomposition of alcohols and of adds at the operating tem- 
perature. 

860. First Case. If the instability of the two temporary com- 
pounds is of the same order they will decompose simultaneously and 

the decomposition becomes: 

fR.CO.R + CCl 



(1) 2R.C0.0Ci,Hsn+i + 2M0 



ketoM 
2CBHan + HiO 



+ 2M0. 



A symmetrical ketone is produced and an unsaturated hydrocarbon 
which, if it is a gas (ethylene, propylene and butylene) has twice the 
volume of the carbon dioxide produced. This was the case in the 
experiments with alumina mentioned above (858). 

If the ester is a methyl ester there is no separation of water, and 
methyl ether, (CHi)sO, is formed. 

861. Second Case. If the catalyst is more active toward adds 
than with alcohols, the decomposition of the complex, (R.CO.O)sM, 
is more rapid than that of the alcohol compound. The water formed 
in reaction (1) has time to react with an equivalent amount of the 
latter and decomposes it to regenerate the alcohol: 

(C^H,„+iO), + H,0 - UO + 2CnHfa^.i.0H. 

aloohol 

This combined with the former reaction gives: 
(2) 4R.C0.0CnHto+i - 2R.CO.R+2CO»+2Ci.H,n+2CaH,H-i.OH. 



There is the simultaneous formation of ketone and alcohol and of 
equal volumes of carbon dioxide and of unsaturated hydrocarbon (if 
it is a gas). This is usually the case with decompositions caused by 
thoria, e.g. at 310^ with ethyl acetate^ propyl acetate, propyl propionate, 
iscbutyl acetate, and ethyl caproate.^ 

* Titania prepared by the precipitation of the hydroxide from the sulphate cata- 
lyies the decomposition of ethyl acetate two thirds according to the equation: 

(1) CHiCQiCiHi - C.H« + CHiCOOH 
and one third according to: 

(2) 2CH,C0iCH, - CH,COCH« + CO. + CH4 + H|0 

Titania prepared by precipitating blue titanoua hydroxide from a solution of 
titanouB chloride, and then allowing this to oxidise to the white titanic hydroxide 
while suspended in the solution, catalysed the reaction one third according to (1) 
and two thirds according to (2). 

Thoria prepared by ignition of the nitrate giTes very little ethylene, as was 
found by Sabatier, but thoria prepared by predpitation of the hydroxide giTes 
almost as much ethylene as would be called for by (2). 

Alumina does not only give reaction (2) but a fifth to two thirds of the ethyl 
acetate is decomposed according to (1). The method of preparation of the cata- 
lyst and the length of time it has been used determine the proportions.— 
Homer Adkins. 



862 CATALYSIS IN ORGANIC CHEMISTRY 310 

862. Elevation of temperature accelerates the decomposition of 
the unstable intermediates and tends to bring the reaction nearer to 
(1). This is the case with laobutyl acetate over thoria at above 350^ 
and for ethyl caproate at about 360^. Besides when the temperattu*e 
becomes high, the alcohols suffer more or less decomposition into hy- 
drogen and aldehydes, easy to recc^nize, and these may be partially 
split up into hydrocarbons and carbon monoxide. 

863. Third Case. If the catalyst is less active with acids than 
with alcohols, the temporary complex, (R.CO.O)sM, will be decom- 
posed only slowly. The water set free by the rapid decomposition of 
the alcohol complex will act on the above to set the acid free: 

(R.CO.O)iM + H2O = MO + 2R.C0.0H. 

Mid 

In this case the formation of ketone and liberation of carbon di- 
oxide are less important : the production of unsaturated hydrocarbon 
and setting free of acid predominate. 

This is what takes place over tiiania with esters of acetic, propi- 
onic, butyric and valeric acids, which adds it decomposes more slowly 
than it does the alcohols. 

864. Fourth Case. The exaggeration of the preceding case is 
found with those catal3rsts which are active with alcohols but are in- 
capable of decomposing acids. This is the case with various catal3iic 
oxides, e.g. thoria and titania with esters of benzoic and toluic adds, 
and with boric anhydride with esters of aliphatic adds, since boric add 
can form the temporary complexes with the alcohols only. In such 
cases we may write the reaction as follows: 

2R.C0.0CnH,a+i + MO = M(OCaH,„+i), + (R.CO)iO 

anhydnde 

= MO + 2C„Hto + H«0 + (R.CO),0 
= MO + 2CnHto + 2R.C0tH . 

•oid 

There will be a total regeneration of the acid with the formation 
of the imsaturated hydrocarbon exclusively. It has been found that 
ethyl bemoate is decomposed into benzoic acid and ethylene by thoria 
above 400^, as in Colson's sealed tube. 

Likewise eOiyl valerate catalyzed by boric anhydride above 400 , 
gives ethylene and valeric acid exdusively. 

865. Methyl esters which can give only methyl ether are difficult 
to decompose : the reaction, which requires a higher temperature, 
yields exclusively carbon dioxide, methyl ether and the keUme, fre- 
quently partially decomposed, and resulting water which may saponify 
a part of the ester to form free acid and methyl alcohol. 



311 DECOMPOSITION OP ESTERS OF ORGANIC ACIDS 868 

Catalytic Decomposition of Formic Esters 

866. In the absence of catalysts, formic esters are quite stable : 
when the vapors of ethyl formate are passed through a glass tube at 
400^, no appreciable decomposition is observed, but the decomposition 
is very rapid in contact with catalysts that decompose formic acid 
(821), and takes place at temperatures lower than those required for 
the esters of other aliphatic acids, but higher than those required by 
formic acid. 

Sabatier and Mailhe have shown that this decomposition takes 
place according to two different reactions at the same time, the one 
similar to the usual decomposition of esters of other aliphatic adds: 

(1) 2H.C0,CnH,n-n « H.CO.H + CO, + (C«Hta+,),0 

fonnmldohyde ethor 

the ether surviving only in the case of methyl ether, splitting in other 
cases into water and unsatiurated hydrocarbon (HsO + 2CnH^ ; the 
other always predominating, is peculiar to formic esters: 

(2) H . COjDuEt^i = CO + CnH>n.Hi.OH. 

aloohol 

A portion of this alcohol is decomposed at the reaction tempera- 
ture, either into aldehyde and hydrogen (with metals or manganous 
oxide), or into unsatiurated hydrocarbon and water (with thoria and 
alumina), or in both ways (with mixed catal3rsts). The water result- 
ing from reaction (1) or from the dehydration of the alcohol formed 
according to equation (2) can saponify a part of the ester to alcohol 
and free formic add which is then decomposed in the way already 
described (821).« 

867. Metals. Finely divided metals can easily cause the decom- 
position of formic esters, nickel above 220^, platinum above 270^, and 
copper above 350^. Reaction (2) greatly predominates and gives the 
alcohol which the metal breaks down to aldehyde, along with the car- 
bon monoxide, l^th copper or with nickel at a low temperature 
the aldehyde survives, but with platinum or with nickel at a high 
temperature (618) it is largely destroyed. 

868. Titania. Reaction (2) takes place almost exclusively. From 
methyl formate^ methyl alcohol and methyl ether resulting from its 
partial dehydration are obtained. The gas collected over water is 
practically pure carbon monoxide without the dioxide because the for- 
mic acid, under these conditions, gives only carbon monoxide and 
water (825). 

* Sabatub and Mailhb, C&mpt. rend,, 154, 49 (1912). 



869 CATALYSIS IN ORGANIC CHEMISTRY 312 

869. Zinc (hdde. It is again reaction (2) that predominates, but 
the formic add that is set free by the water resulting from the dehy- 
dration of the alcohol, is decomposed by the catalyst into water and 
carbon dioxide which is found mixed with the monoxide. 

870. Thoria. Reaction (2) predominates but is accompanied by (1) 
which furnishes a certain amount of formaldehyde which is diminished 
as the reaction temperature is raised. 

S a — DBCOMPOSmON OF ESTERS IN THE 
PRESENCE OF AMMONIA 

871. When the vapors of an ester of an organic monobasic acid 
mixed with ammonia are passed over thoria or (dumina at about 
480-90^, nUriles are obtained by the elimination of water and alcohol 
or of decomposition products of the alcohol. 

Methyl esters give the alcohol, partially split into methyl ether and 
water or into formaldehyde and hydrogen. 

Elsters of other aliphatic alcohols give the unsaturated hydrocarbonSy 
while phenol esters 3deld phenol the major portion of which remains: 

R.CO.OR' + NH, - H,0 + R'OH + RON. 

Eihyl acetate gives ethylene and acotoniirile and ieoamyl acetate yields 
amylene and acetonitrile, while phenyl acetate liberates the same nitrile 
and phenol. 

Analogous results have been obtained with esters of propionic, bu- 
tyric, isovaleric, nonylic and caproic adds. 

Methyl benzoate gives more than 80% of behzonitnle with methyl 
alcohol and formaldehyde. Ethyl and isopropyl bemoates yield the 
same nitrile. The esters of the three toluic adds behave in the same 
way. 

Ethyl a- and fi-mapJUhoates are almost quantitatively transformed 
into the a- and fi-maphihonitriles. 

Ethyl phenyUacetate gives an excellent yield of benzyl cyanide.* 

§ 3* — BSTERS OF DIBASIC ACIDS 

872. The catalytic decomposition of esters of dibasic acids has 
been as yet very incompletely studied. 

Catalytic oxides such as alumina and thoria cause decompositions 
readily. If we extend to the esters of dibasic adds the interpretation 
above set forth for the action of these oxides, we can predict that an 
oxide, MO, will effect the reaction: 

> Mailhb, BuU. See. Ckim. (4), n, 282 (1918). 



313 DECOMPOSITION OP ESTERS OF ORGAOTC ACIDS 873 

/CO. OR XJO.Ov /OR 

(CHOxC + 2M0 = (CH,).C >! + ]!< 

\ C0.0R NCO.O/ NOR 

ester metal salt alooholate 

If the oxide is at the same time a catalyst for acids and for alco- 
hols, the compounds thus formed will be unstable and will decompose 
as follows: 

(CH,),<^ >f « MO + (CH,)^ po 

anhydride 

/OR R\ 

and: MC - MO + )0. 

\0R B/ 

ether 

The oxide, MO, is entirely regenerated and can carry on the reaction 
indefinitely. We ¥Pill obtain as results of the catalysis, the acid anhy- 
dride, or its debris, if it is unstable, the ether, or in most cases, the 
catalytic decomposition products of that ether, i.e. water and an 
unsaturated hydrocarbon. 

873. These predictions have been verified by Sabatier and Mailhe 
in the case of the neutral esters of oxalic, malonic and succinic acids 
over thoriaJ 

COv 

Oxalic anhydride, • >0, is unknown and the mixture, COs + 

go/ 

CO, is obtained in its place. Malonic anhydride, CH». ^O, is 

equally unstable and decomposes into carbon suboxide, CO : C : CO, 
which polymerizes into reddish products or decomposes into carbon 
monoxide, dioxide and carbon. 

Succinic anhydride is stable if the temperature is not too high and 
can be collected as crystals melting at 177^. If the temperature is 
above 350^, it is deccnnposed into carbon monoxide and dioxide, ethyl- 
ene and condensation products. 

These results have been verified for the ethyl, propyl, iscbutyl and 
isoamyl esters of the three acids: except in the case of the ethyl 
esters, where the stable ethyl ether can be collected, the debris of the 
esters, water and the unsatiurated hydrocarbon, are found.* 

' Sabatibb and MAnaa, BuU. Soe. Chim. (4), zz, 869 (1912). 
* Sabatisb and Mailbx, Loc cU, and unpublished rtsuUs. 



874 CATALYSIS IN ORGANIC CHEMISTRY 314 

With esters of oxalic acid, the catalytic decomposition begins at 
very moderate temperatures and is abeady rapid at 220^: higher tem- 
peratures are required for malcnates and still higher for succinaies. 

A decomposition of this nature has been found in the particular 
case of ethyl oxalaU over alumina: at 200^, ethyl ether, carbon mon- 
oxide and dioxide are obtained, while at 360^, the ethyl ether is re- 
placed by ethylene.* 

874. The catalytic decomposition of ethyl succinate over alumina 
at 400^, according to Senderens, Uberated ethylene and carbon dioxide 
and produced p. cyclohexadione.^^ But Sabatier and Mailhe were not 
able to verify this and obtained only succinic anhydride along with 
ethylene and carbon dioxide. The same results were obtained with 
alumina at 260^. 

Ethyl gluiarate over alumina at 270^, gave only ethylene and glu' 
iaric acid. Ethyl adipate furmshed ethylene and adipic acid at 300^.^^ 
At higher temperatures this should have given cyclapentanone (856). 

* Sbndbbbnb, BuU, Soe. Ckim. (4), 3, 826 (1908). 
^> SsNDBBBNB, BvU, Soc. Chim, (4), 5, 485 (1909). 
u MiCHUDLS, BvU. Soe. Chim. Beige, 37, 227 (1913); C. A., 8, 1106 (1914). 



CHAPTER XX 

ELIMINATION OF HYDROGEN HAUDES OR SIMILAR 

MOLECULES 

875. The elimination of hydrogen halides can take place from a 
single molecule or by condensation from two molecules. Anhydrous 
chlorides are the chief catalysts in both cases. 

§ I. — ELIMINATION OF HYDROGEN HALIDE FROM 

A SINGLE MOLECULE 

876. When an alkyl moruH^loride is passed over a layer of various 
anhydrous metal chlorides in a tube maintained at above 200^ there is 
rapid decomposition into unsaturated hydrocarbon and hydrochloric 
acid: 

CnHjn+iCl ^ HCl "t" C/nMia. 

Methyl chloride alone does not decompose in this way. 

Barium, nickel, ccbalt, lead, cadmium and ferrous chlorides are suit- 
able for effecting this reaction. Primary chlorides are decomposed 
above 260° and rapidly at 300° while secondary and tertiary are still 
more easily acted on. 

The same metal chlorides decompose alkyl mono-bromides or mono^ 
iodides in the same way to form hydrobromic or hydroiodic acids, but 
higher temperatures are required.^ 

The recombination of the imsaturated hydrocarbon with the lib- 
erated hydrogen halide takes place to a certain extent in the tube 
beyond the catalytic chloride and may yield a certain amount of 
secondary or tertiary isomers of the original alkyl hahde. 

Dry barium chloride gives very good results and can effect this 
decomposition indefinitely; if it is dissolved in water after long use, 
there is a small residue of viscous very condensed hydrocarbons with 
a petroleum odor. 

The chlorides of monovalent metals, silver, sodium, and potassium 
are inactive. 

The process applies to monochlor derivatives of cyclohezane and 
cydopentane. It can succeed with unsaturated moruhchUnides and even 

1 Sabatixb and Mailbm, Compt, rend., 141, 288 (1006). 

315 



877 CATALYSIS IN ORGANIC CHEMISTRY 316 

with halogenaied alcchola ' as well as with dichlarcuclohexane which is 
converted to dihydrobemene^ 

877. Anhydxoos ahimimim chloride acts actively in the same man- 
ner, but it has the disadvantage of producing liquid products that 
hinder the continuation of the catalysis. It has been used to trans- 
form propyl chloride into propylene^ 

878. The catalysis can be explained by the assumption of an un- 
stable organo-metallic combination derived from the alkyl chloride: 

C3^a+i.Cl + BaCU = HCl + Cl.Ba.CaHtoCl. 

The mixed complex thus formed would decompose rapidly to give 
the unsaturated hydrocarbon: 

Cl.Ba.CnHtn.Cl = BaCU + C,Htn. 

The regenerated chloride can repeat the cycle of reactions indefi- 
nitely. The formation of such a mixed complex can be observed in the 
case of anhydrous alufninum chloride: mixed with isobutyl chloride 
at -10^, no reaction takes place but if the mixture is warmed to 0^, 
hydrogen chloride and isobutylene are evolved and an intensely 
colored liquid is formed. 

At 300^y ferric chloride causes the elimination of hydrogen chloride, 
but no iacbiUylene is formed; a solid of high molecular weight is 
produced. 

Chromic chloride, CrCU) does not act.* 

879. As has been mentioned above (876), this kind of catalysis can 
be applied to poly-halogen derivatives. 

Heptachlorpropane, CCls.CCU.CHCU, is decomposed above 250^ 
by cuprous chloride with the elimination of hydrogen chloride to give 
pentachlor'propylene, CCls.CCl :CCls at the same time that a split- 
ting of the molecule yields chloroform and ietrachlorethylene, CsCU* 
Zinc and barium chlorides have little action.* Aluminum chloride gives 
a reaction which is limited by the reverse combination of the chloro- 
form with the tetrachlorethylene (902). 

880. Benzyl chloride is easily decomposed by various anhydrous 
chlorides particularly those of baritun and nickel, into hydrochloric 
acid and a very high molecular weight compound of the empyrical 
formula CrHg, previously discovered by Cannizzaro and identical with 

* Badischx, Oerman patent, 255,519 (1913). 

* Badischb, French patent, 441,203. 
« Kbbbz, Annalen, aaz, 306 (1885). 

* Sabatibb and MAn^HB, Compt. rend,, 141, 238 (1905). 

* BottSBKBN, VAN DBB ScHBBB End DB VooT, Bec Trav. CMm, Pays-Bos, 34t 
78 (1915). 



317 ELIMINATION OF HYDROGEN HALIDES 884 

that formed by the dehydration of benzyl alcohol (714) ^ and which 
is perhaps hexaphenyUcydohexane, (C«Hs.CH)6. The reaction is: 

x(C.H,.CH,Cl) = xHCl + (CiH,.CH),. 

881. Anhydrous metatUc oxides can likewise effect the decomposi- 
tion of alkyl halides in consequence of the formation of a certain 
amount of the corresponding chloride. When isobutyl chloride is 
passed over alumina at above 250^, the slight dissociation of the alkyl 
chloride at that temperature can accoimt for the formation of a little 
chloride or oxy-chloride of aluminum which starts the catalytic action 
and the amount of which increases rapidly in consequence of the hyd- 
rochloric acid evolved. This is the explanation of the decomposi- 
tions of alkyl chlorides with alumina that have been described.* 
Thoria above 390^ has been proposed for the decomposition of tetror 
chlorethane into triMoreOiylene: there is the simultaneous formation 
of carbon hexackloride^ CsCU.* 

882. It is probably the formation of nickel chloride also, to which 
may be attributed the identical catalytic effect of reduced nickA on 
alkyl chlorides in the presence of hydrogen; the decomposition takes 
place easily above 25Kf.^^ 

§ 2. — CONDENSATIONS EFFECTED BETWEEN MOLECULES 
WITH ELIMINATION OF HYDROGEN HALIDE 

883. Anhydrous aluminum chloride causes condensation with elim- 
ination of hydrochloric add between aromatic hydrocarbons and various 
alkyl or cyclo-alkyl chlorides and bromides effecting the synthesis of a 
large niunber of aromatic compounds. This is the basis of the Friedel 
and Crafta eynihesis.^^ 

m 

I. Alkylation of Aromatic Hydrocarbons 

884. Method of Operating. It is common to use a large well dried 
flask with a stopper through which passes a very large tube the upper 
end of which is closed by a stopper and which permits the introduc- 
tion of the solid aluminum chloride and on the side of which is fused 
a tube inclined upward and connected with a reflux condenser. The 
hydrogen chloride which is evolved escapes at the top of this con- 

' Gannizzabo, Annalen, 92, 114 (1854). 

• Sbndbbbnb, BvU, Soe. Chim. (4), 3, 823 (1008). 

* Chsm . Fabb. BucxaUi Oerman paUrU, 274,782, /. Soc, Chem. Ind,, 33, 807 
(1014). 

^* Sabatubb and Mauax, Compt, rend., Z38, 407 (1004). 

u Fbibdbl and Cbaftb, Ann. Chim. Phye. (6), i, 480 (1884). 



886 CATALYSIS IN ORGANIC CHEMISTRY 31« 

denser and may be led into a tarred flask of water, the gain in weight 
of which serves as a means of following the reaction so that it may be 
stopped when the theoretical amount of this acid has been Uberated. 

The aromatic hydrocarbon in large excess (usually 10 times the 
calculated amount) is mixed with the halogen compound with which it 
is to react and put into the flask which is warmed on the water bath. 
The well pulverised anhydrous aluminum chloride is added in small 
portions, 2 to 20 g. at a time. Whenever the evolution of hydrogen 
chloride dies down a fresh portion of the chloride is added. 

If the alkyl halide is a gas (methyl or ethyl chloride), it may be 
passed iolto the flask after the addition of a certain amount of alu- 
minum chloride. 

When the reaction is considered finished, the flask is cooled and 
the mixture is poured into a large excess of cold water acidulated with 
hydrochloric add; the oily layer is separated, washed and dried and 
fractionated. 

The simplest case is methyl chloride with bemene: 

CeH« + CH,C1 - HCl -h C<Ht.CH, . 

toluene 

885. Often excellent yields are obtained but the chief product is 
always accompanied by others, particularly the di- and tri- sub- 
stituted, resulting from the reaction of the first product with a second 
molecule of the halide. Thus in the simplest case, that of methyl 
chloride on bensene, the latter reacts with the toluene that is formed 
to give a mixture of the xylenes. These can react in their turn to yield 
trimethyUfenzenes (1, 2, 4 and 1, 3, 5) and if the reaction is prolonged, 
tetraineihylrbenzene{l, 2, 4, 5), then pentameihyU and finally hexor 
methylrbenzene are formed. 

By stopping the reaction when the calculated amount of acid has 
been evolved these complications are avoided for the most part. 

The yield of monosubstituted hydrocarbon is considerably in- 
creased when an amount of aluminum chloride equal to 15 or 20 % of 
the weight of the alkyl chloride is used. 

The use of carbon disulphide as a solvent sometimes facilitates the 
reaction.^ 

Alkyl chlorides, bromides or iodides may be used interchangeably, 
the latter evolving hydrogen bromide and iodide. 

886. In place of using aluminum chloride as above described, the 
flask may be filled with aluminum turnings (previously cleaned by 
boiling with alcohol and washing with ether) and a current of dry hydro- 

^ AnschOts, Anndlen, 235, 207 (1886). 



319 ELIMINATION OF HYDROGEN HAUDES 889 

gen chloride passed.^ Alimunum turnings may be used with mercuric 
chloride which attacks the metal rapidly forming the chloride ^* 

In some cases the aluminum chloride is put in the flask first and 
covered with carbon disulphide and then the mixture of the two sub- 
stances that are to react is run in. 

887. Reversal of the Reaction. The addition of alkyl groups may 
be limited by the reverse reaction of removing them, and this is also 
catalyzed by aluminufn ddoride. 

When the poly-alkyl benzenes are treated with aluminum chloride and 
a cmrent of hydrogen chloride, the alkyl side chains are eliminated as 
alkyl chlorides. ^* From hexaine(hyl4>enzene we may pass to pentamethylr, 
to tetrameOiyU (1, 3, 4, 6) and (1, 3, 4, 6) to trimethyU (1, 3, 4) and 
(1, 3, 5) to meta and para xylenes, then toluene and finally benzene.^* 

888. It may happen that side chains are taken off of one molecule 
and put on another in consequence of splitting off an alkyl halide 
which then reacts with the other molecule. 

Thus poly-ethylrbemenes in presence of benzene and aluminum chlo- 
ride, retrograde towards eOiylrbenzeney particularly in a current of 
hydrogen chloride which carries off the ethyl chloride.^' 

Ethyl-benzene kept in contact with aluminum chloride furnishes 
simultaneously benzene and diethyHenzene. Isomerizations may result 
from an alkyl group being taken off and put on again. From p.xylene 
we may get m.xylene and inversely; pseudocumene (1, 3, 4 -tri-methyl- 
benzene) may give meeityleneO-, 3, 5).^* 

889. Results Obtained. The reaction goes well with various 
aromatic hydrocarbons, benzene and its homologs as well as with 
napfithalene ^^ and diphenyL The homologs of benzene frequently 
give better results thaji benzene itself. 

It was developed first for alkyl mono-chlaridee but may go equaUy 
well with cydohezyl monochlorides: cydoheocyl chloride and beruBene 
give phenyl-cyclohexane.*^ 

^ Stockhaubxn and Gattebmakn, BerichU, 25, 3521 (1891). 

^« Radzubwanowski, BerichUf 28, 1135 (1895). 

^ Jacobbbn, BerichU, 18, 339 (1885). 

!• This reaction has been extensively used for the manufacture of tohiene from 
the xylenes. — E. E. R. 

^' Radzixwanowski, BeriehiSf 27, 3235 (1894). — Boxdtxbb and Haisb, BulL 
8oe. CHm. (4), 19, 444 (1916). 

^* ANBCHtJrz and Immxndobf, BerichU, 17, 2816 (1884), and 189 657 (1885). 

^* It is remarkable that when a solution of naphthalene in benaene is treated 
with phthalio anhydride in the presence of aluminum chloride, the naphthalene 
reacts to the exclusion of the bensene. — Hxllxb and ScBthJUB, BenehU, 4X9 8627 
(1908). — E. E. R. 

** KouBSANor, /. RuiMon Phys. Chem. Soc., 339 527 (1901); BuU, 80c, Ckim. 
(3), 28, 271 (1902). 



890 CATALYSIS IN ORGANIC CHEMISTRY 320 

It is also applicable to the chlormethyl ethers, R.O.CHsCli which 
form the ether R.O.CHtR' with an aromatic hydrocarbon, R'H. 
With benzene the reaction goes regularly in the cold but the yield ia 
only 30%, because benzyl chloride is also formed by a side reaction 
which liberates the alcohol, R.OH (818)." 

The reaction applies to derivatives of aromatic hydrocarbons which 
are chlorinated in a side chain, e,g. benzyl chloride, CeHs.CHiCl.^ 

Unsaturated monochlorides or monobromides may be used. Thus 
vinyl bromide f CH%: CHBr, condenses with benzene to form styrene.^ 

890. Dihalogen derivatives may also be used. Ethylene chloride 
reacts with benzene to form synmietrical diphenyl-ethane*^ and 1, Jf- 
dibromrethylene forms i, l-diphenyl^ethylene, CHi : C (CeH^)!.'* 

Ethylidene chloride, CHs.CHCli, gives similarly 1, l-diphenyU 
ethane, CH«.CH(C6Hft)s, but the reaction may be complicated by the 
fonnation of eihylrbenzene and dihydro-dimethylranthracene^* 

Benzol chloride, CeHi.CHCli, with 5 parts of benzene and a little 
aluminum chloride, yields triphenyl-meOiane,^ which may also be 
formed from benzene and chloroform, CHCU.'' 

n. Synthesis of Ketones 

891. The Friedel and Crafts reaction is still more easily applied to 
the production of ketones, by the reaction of aromatic hydrocarbons with 
carbonyl chloride, or with the chlorides of aliphatic or aromatic acids. 

Thus carbonyl chloride and benzene form benzophenone: 

COCl, + 2C«H« - 2HC1 + C«H,.CO.CJH*. 
Acetyl chloride produces acetophenone from benzene : 

CHi.COCl + CeH* - HCl + C«H|.CO.CH,. 

892. For these preparations equal molecules of the hydrocarbon 
and the acid chloride are mixed and carbon disulphide, ligrcine or 
nitrobenzene is added till a limpid liquid is obtained. Care must be 
taken to protect from all moisture. This solution is added a little at a 
time to another flask which contains an equal volume of solvent and 

*^ SoifMSLBT, Compi. rend., 157, 1443 (1913). 

*> Fboedsl and Csafts, Ann. Chim. Pkys. (6), x, 478 (1884). 

" ANBCHt)«K, AnndUn, 235, 231 (1886). 

s« SiLVA, Compt. rend., 89, 606 (1879). 

u Demolx, BerichU, xa, 2245 (1879). 

•• GsimBBBSsa, BvXL. Soc. Ckim. (2), 49, 579 (1888). 

^ LiNEBUBGSB, Atner. Chem. Jour., 139 270 (1891). 

*• Fbibdxl and CaAirre, BvXL. Soc. Cfdm. (2), 37, 6 (1882). — E. and O. 
Fischer, Annalen, 194, 252 (1878). — Allen and E5llikxb, AnnaUn, 227, 107 
(1885). 



321 ELIMINATION OF HYDROGEN 898 

aluminum chloride equal in weight to the acid chloride.'* The mix- 
ture is warmed slowly on the water bath till no more hydrogen chlo- 
ride is evolved. 

Niirobemene as a solvent has the advantage of dissolving alu- 
minum chloride.'^ 

The aliuninum chloride may be added a little at a time to the 
mixture of the hydrocarbon and the acid chloride. 

893. Results. Acetyl chloride^ CHs.COCl, condenses with benzene 
to form acetophenone, CeHj.CO.CH*," while benzoyl chloride, CeHs.- 
COCl, gives bemophenone, CeEU.CO.CeH*** which may also be ob- 
tained by condensing benzene with carbonyl chloride. Benzoyl bromide 
may be used with benzene and aluminiun bromide.** 

Chlor- brom-, or nitro- ring substitution products of the aromatic 
acid chlorides may be used with the same facility. Thus mjiHrchen- 
zoyl chloride, OsN.C6H4.COCl, reacts with bemsene to form m.nitro' 
benzophenone, OsN.C6H4.CO.C6H6/^ and similar compounds can be 
obtained from the chlor ** and brom •• derivatives. 

The chlorides of dibasic acids can give a double reaction to form 
diketones. Thus euccinyl chloride and benzene furnish 1, JirdiphenyU 
butadione(l,4), C«H».CO.CHt.CHj.CO.CeH,. The reaction is car- 
ried out in carbon disulphide.'' 

Malonyl and glutaryl chlorides react similarly.*^ 

On account of its tautomeric nature, pMhalyl chloride can give 
different products according to the way the reaction is carried out. 

PhlhalopJienone, ^ anOiraquinone, diphenyl-^mOirone, ^ 

CCCeHO. yCOv C(C.Hs), 

/ V CeH/ )CeH4, / V 

** It is better to calculate the amount from its molecular weight and that of 
the acid chloride; to 1 mol. RCOCl, 1 mol. AlCU - 133.5, is required but 10% 
excess is of advantage. — E. E. R. 

><» BsHN, German patent, 95,001 (1897). 

>^ Fbubdxl and CRAirrs, Ann. CHm. Phy$. (6), 14, 455 (1888). 

** Fbibdxl and Crafts, Ann. Chim. Pkys. (6), x, 510, and 518 (1884). 

** OuviBB, Eee. Trat. Chim. Payt-BoB, 37, 205 (1918). 

*« GxiGT and KOnigs, BerichU, x8, 2401 (1885). 

*• OvKBTOK, BerichU, 26^ 29 (1893). — Hantzsch, BerichU, 24, 57 (1891). — 
DxiftJTH and DrmucH, BerichU, 23, 3609 (1890). 

** Cathcabt and Mxtbb, BerichU, 25, 1498 (1892). 

" Glaus, BerichU, 20, 1375 (1887). 

** AuGBB, Ann. CHm. Phyt. (6), 22, 349 (1891). 

•* Fbibdxl and Cbaits, Ann. Chim. Phys. (6), x, 523 (1884). — Baxtxb, 
Annaien, 202, 51 (1880). 

^ Halubb and Gutot, BvU. 80c. Chim. (8), 17, 873 (1897). 



894 CATALYSIS IN ORGANIC CHEMISTRY 322 

, benzoyl-benzoic acid,^^ CeHi.CO.CeHi.COOH, and other products^ 
are obtained. 

Acid chlorides may react with pyridine or quinoline in the presence 
of aluminum chloride to give ketones when traces of thionyl chloride 
are present. From benzoyl chloride and pyridine, pyridylrphenyUketone 
is obtained:^ 

C«H|.C0.C1 + CjHjN - HCl + CeHj . CO . C,H«N. 

894. ThiophosgenCi CSCU, reacts with aromatic hydrocarbons to 
form thioketones: thus with benxene, ihicbenzophenone, CeHs.CS.- 

in. Formation of Amides 

895. By the action of carbamic chloride, Cl.CO.NHs, aromatic 
amides are formed: thus from benzene, benzamide, CfHs.CO.NHs is 
obtained.** 

IV. Formation of Cyclic Compounds 

896. Methylene chloride condenses with diphenyl, CfHs.CtHs, to 

form fluorene, 

C«B[4V 

)CH,.^ 

cusy 

897. Tetrabrometfaane (1,1,2,2,), or acetylene tetrobromide, reacts 
with benzene to form anthracene: ^ 

BrCHBr yCHv 

CeHe + • + CeHe = C«H/ • )C«H4 + 4HBr. 

BrCHBr \CH/ 

Condensation may take place between two or more molecules of a 
chlor-compound. Thus ^-^henyUeOiyl chloride , CeHs.CHs.CHsCl, re- 
acts vigorously with aluminum chloride in carbon disulphide or lig- 
rolne to form an insoluble resin (C6H4.CHsCHs)x. 

Dissolved in 6 parts of ligrolne with 1 part of aluminum chloride, 

i-phenylrbytyl chloride gives an excellent yield of tetrahydro-naphihar 

lene: 

/CHf . CHs . CMs / CHf . CMf 

CeSi = CeSi • H" HCl. 

\H CICH, \CH,.CH, 

^ ScHBiBXR, iinnolen, 389, 121 (1912). 

^ CopiSABOW, /. Chetn, Soc,, iii, 10 (1917). 

« WoLTFENSTBiN and Habtwich, BerichUf 48, 2043 (1915). 

«« BxBORXXN, BerichU, 21, 341 (1888). 

« Gattxbmann, AnnaUn, 244, 29 (1888). 

«• Adam, Ann. Chtm. Phya, (6), 15, 253 (1888). 

«^ ANTSGHtiTS, Anndlen, 235, 165 (1886). 



323 ELIMINATION OF HYDROGEN HALIDES 900 

Similarly S-phenylrperUyl chloride gives phenyUcydoperUane boiling 
at 213^« 

898. Mechanism of the Reaction. We have shown above how the 
r61e of the aluminum chloride in the Friedel and Crafts reaction may 
be explained (173). The catalytic nature of the action is not doubted 
.though sometimes it is necessary to employ large amoimts of the salt, 
sometimes larger than the amoimt of the aromatic hydrocarbon. This 
is the case when the aluminum chloride combines with one of the 
products of the reaction and is thus withdrawn from its catalytic 
fimction.** 

899. Other Catalytic Chlorides. Several anhydrous metallic chlo- 
rides can be employed in the same way as aluminum chloride in the 
Friedel and Crafts synthesis: zinc, ferrous, ferric and stannic chlorides 
and anHmony pentachloride. 

The use of ferric chloride is quite advantageous in preparing ke- 
tones.*® Thus benzoyl chloride and benzene give benzophenone.*^ Its 
action, like that of the other chlorides mentioned above, is milder 
than that of aluminum chloride. For that reason these chlorides some- 
times give rise to less formation of byproducts. 

For the preparation of benxophenone, the following comparative 
yields have been obtained:'^ 

With aluminum chloride 70-71 % 

ferric chloride 60--62 

zine chloride 28-32 

Aluminum chloride serves poorly for condensing toluene with chlor- 
methyl ethers (889), while good results are obtained with antimony 
pentachloride and particularly with stannic chloride,^ 

The use of zinc chloride, or better metallic zinc which immediately 
forms some of the chloride, has been recommended for reactions with 
naphthalene.^ Thus the di-maphthyl ketones are prepared by the 
action of zinc on a mixture of naphthalene with a- or j3-naphthoyl 
chlorides.** 

900. A different isomer may be obtained when other chlorides are 
substituted for the aluminum chloride. Isobutyl chloride condensed 

^* VON Ba^UN and Dbutbch, BerichU, 45, 1267 (1912). 
«• Hbllbb and ScHtLXX, BeriehU, 41, 3627 (1908). 

•• NxKCKi, BeriehU, 30, 1766 (1897), and 32, 2414 (1899). — Mbissbl, BerichU, 
33, 2419 (1899). 

^ Qangloff and Hsndbbson, /. Amer, Chem. Soc,, 39, 1420 (1917). 
" SoiooDLiT, Compt. rend., 157, 1443 (1913). 
" Albxtxf, Mith. de trantfonn. des comb, organ., Parii, 1891, 186. 
*« Obucabbvic and Mxbz, BeriehU, 6, 1242 (1877). 



901 CATALYSIS IN ORGANIC CHEMISTRY 324 

with toluene in the presence of ferric chloride gives p.methyJriacbutyl' 
bemenCf while in the presence of aluminum chloride the meta com- 
pound is obtained.^' 

Fonnation of Aromatic Amines by Hofmann's Reaction 

901. Traces of cuprotis iodide can readily effect the condensation 
of primary aromatic amines with phenyl bromide, with elimination of 
hydrobromic acid. The acetyl derivative of the amine may be used. 
Thus by boiling 90 g. brombenxene, 10 g. acetaniUde, 6 g. sodiimi 
carbonate and a little cuprous iodide for 15 hours, acetyJrdijih/enyU 
amine is obtained and this can readily be transformed into diphenyl- 
amine. The cuprous iodide can be replaced by copper and iodine or 
even by copper and potassium iodide.^* 

The presence of copper powder greatly facilitates the action of 
ammonia imder pressure at 170^ on chlor^itro-bemene to form amino- 
nitro-bemene.^ 

It is also useful in the similar reaction of aniline or its homologs on 
o-chlor-benzoic and Bti^hlor-nitro-benzoic adds in the preparation of 
the corresponding amino compoimds.*' 

likewise pyridine heated 7 hours to 250^ with benzyl chloride and a 
Uttle copper powder gives a good yield of ^-benzyU and i-iemyU 
pyridine. Ethyl iodide and pyridine give the eihylrpyridines under the 
same circumstances. The copper can be replaced by cuprous chloride. 
Aluminum and magnesium powders give poorer results. ^^ 

Condensations in the Aliphatic Series by Anhydrous Chlorides 

902. The use of ferric chloride enables us to effect important con- 
densations in the aUphatic series. Thus with propionyl chloride in the 
presence of alcohol, two molecules of the add chloride condense to 
form the ester of a keUhocid:^^ 

CH,.CH,.C0C1 + CH,.CH,.C0C1 + C«H»OH - 
CHi . CH, . CO . CH (OH.) . CO,CA + 2HC1. 

903. Chloroform condenses with perUachloreihane on contact with 
aluminmn chloride with evolution of hydrogen chloride to form 
heptachlor-propane : ^ 

CHClj + CCU.CHCl, - HCl + CHCl, . CCU . CCU. 

H BiALOBRZKSKi, BerichUf 30, 1773 (1897). 

•• Goldberg, BerichU, 40, 4541 (1907). 

" Ullmann, Annalerif 355, 312 (1907). 

** CHicmBABiNB and RTUiismN, /. Rusnan Phys, Chem. Soc., 47, 1297 (1916). 

•• Hamonet, Butt. 80c. Chim. (3), 3» 334 (1899). 

•• Puns, /. prakt. Chem. (2), 89, 414 (1914). 



326 ELIMINATION OF HYDROGEN HALIDES 904 

§ 3. — EIIMINATION OF A MOLECULE OF AN 
ALS:ALINE CHLORIDEy BROMIDE, OR IODIDE 

904. The action of the aromatic halogen derivatiyes, phenyl chlo* 
ride, bromide, and iodide on the alkali salts of phenol should form 
phenyl ether, but practically the yield is trifling. It becomes very high 
when the reaction is carried on imder pressure at 150^ to 200^ in the 
presence of finely divided copper as catalyst. The yield reaches 25 % 
with the chloride, 82% with the iodide and 78% with the iodide. 

This process may be applied to the formation of ethers of diphe- 
nols.** 

*^ Ulucann and Sfonaqil, Annalen, 360, 83 (1907). 



CHAPTER XXI 

DECOMPOSITIONS AND CONDENSATIONS 

OF HYDROCARBONS 

905. The action of high temperature on hydrocarbons is to dis- 
sociate the molecules, from which hydrogen tends to separate, at the 
same time that it produces a greater or less breaking up of the mole- 
cules into groups, CHs, CHs, and CH which are capable of uniting to 
form new complex molecules. There result complicated mixtures of 
varied constitution to which Berthelot has given the name of pyro^ 
genetic equilibria which as the temperature rises tend to produce larger 
and larger proportions of hydrogen and methane along with substances 
very rich in carbon and very condensed hydrocarbons. 

906. The petroleum industry has taken advantage of reactions of 
this sort in the process known as '' cracking" This process, which was 
accidentally discovered at Newark, N. J., in 1861, consists in carrying 
petroleiun vapors to high temperatures, above a dull red. Along with 
usable gases, new hydrocarbons are produced which increase the pro- 
portion either of gasoline or of heavy oils as compared with the original 
oil. 

The effect of temperature begins to be felt at about 325^ but is not 
important below a red heat. The presence of catalysts lowers the 
temperature of these reactions and makes them easier to carry out. 
The finely divided metals, capper, iron, ccbaUf nickel, platinum, mag- 
nesium, and aluminum can be employed and so may the anhydrous 
oxides, tUania, zinc oxide and alumina, etc.^ 

It is important to know the results of the pyrogenetic decomposi- 
tion of the hydrocarbons in the absence of catal3r8ts. 

From this point of view, benzene, petroleums and the coal tar hy- 
drocarbons known as solvent naphtha have been the most studied. 

907. Benzene is hardly affected below 500^, at which it begins to 
decompose into diphenyl, the formation of which increases till it 
reaches a maximmn at 750^. It is accompanied by diphenyl-bemene : 
carbon is deposited and hydrogen set free without any production of 
acetylene or of naphthalene below 800^.' 

^ Zeunsbj, /. Russian Pkys. Chan, Soc,, 47, 1808 (1915). 
' Zanxiti and Egloff, /. Ind. Eng. Chem., 9, 356 (1917). 

326 



327 DECOMPOSITIONS OF HYDROCARBONS 910 

908. American petroleum^ under the action of heat alone, gives in- 
creasing amounts of gas from 450^ to 875^, while the density of the 
liquids produced increases also with the temperature. Between 450^ 
and 600^, the products formed contain more tolvene than xylene, more 
xylene than benzene, and neither naphthalene nor anthracene. At 650^ 
the proportion of benzene is still lower than that of toluene but above 
that of xylene. From 700^ to 850^, benzene is more abimdant than 
toluene and especially than xylene. The formation of naphthalene 
begins at 750^ and that of anthracene at 800^ and both increase rap- 
idly with the temperature. 

For 100 parts of petroleum thus treated, the benzene in the prod- 
uct reaches its maximum of 4.7% at 750^, toluene its maximiun of 
3.1 % at 650^1 and xylene its maximum of 1.9 % at 700^. At 800^ we 
have 2 % naphthalene and 0.3 % anthracene. These aromatic hydro- 
carbons are associated with various aliphatic' 

909. Solvent naphtha contains considerable amounts of higher 
hydrocarbons. When it is heated in steel tubes under 11 atmospheres 
pressure to 500-800^, it yields considerable amounts of lower hydro- 
carbons. In the product, benzene reaches its maximum of 42.5% at 
800^ and toluene its maximum of 39.9 % at 750^. But as the tempera- 
ture is raised higher and higher the yield of Uquid decreases rapi(Uy in 
consequence of the more abundant production of gaseous products and 
of materials poor in hydrogen, the real maximum yield based on 100 
parts of solvent naphtha is:^ 

Benzene 15.9% at 800^ 

Toluene 20.6% at 750®. 

Under the action of a red heat, pinene gives a large number of hy- 
drocarbons, both gaseous and Uquid, among which have been found 
benzene, toluene, maylene, naphthalene, anthracene,^ methyUarUhracene 
and phenanthrene.^ 

By operating at a barely visible red, along with a terpene isomeric 
with pinene but boiling higher, iaoprene, CftHg, benzene and its homo- 
logs, and poly-terpenes are formed.' 

Action of CataljTsts. 

910. The presence of catalysts usually enables us to carry out the 
same reactions at lower temperatures which is more favorable to the 
preservation of sensitive products that may be formed. Usually 

* EoLOFF and Twoianr, /. Phy$. Chem., ao, 121 (1916). 

* EoLonr and Moobb, /. IndL Eng, Chem., 9, 40 (1917). 

• Bbbthslot, Ami. CMm. Phyt. (3), 39f 5 (1853), and (4), 16, 166 (1869). 

• ScBUi/rK, BeriehU, xo, 114 (1877). 

v Tnj>SN, Ann. Chim. PhyB. (6), 5, 120 (1886). 



911 CATALYSIS IN ORGANIC CHEMISTRY 328 

niekd and iron act violently tending to produce very advanced dehy- 
drogenation with charring more and more intense as the temperature 
is raised. 

911. Al^khatic Hydrocarbons. Methane is only slightly attacked 
by nickel up to 360^ but towards 390^ the deposition of carbon is ap- 
preciable.* 

The decomposition is not yet rapid at 010^ at which methane 
heated 10 minutes in a porcelain tube, without catalyst, gives only 
10% of hydrogen. The presence of silica in the tube does not in- 
crease the decomposition, but with lime the proportion of hydrogen 
reaches 35%, with wood charcoal, 69% while with metaUie iron it is 
73%.* 

Ethane decomposes slowly above 325^ giving carbon, methane and 
free hydrogen. 

Penlane decomposes in an analogous way : at 350-400^ methane is 
produced with intermediate hydrocarbons and carbon is deposited on 
the nickel. 

Lengthening the carbon chain makes these decompositions more 
easy;^® but only above 550^ and towards 600^ are the Uquid hydro- 
carbons such as are found in Pennsylvania petroleum attacked. 

912. Unsaturated Hydrocarbons. If a current of ethylene is passed 
over reduced nickel heated above 300^ the nickel can be seen to swell 
up into a voluminous black material which finally fills the tube and 
chokes it up: all the ethylene disappears and a gas is obtained con- 
taining ethane, methans, and hydrogen. The proportion of ethane is 
less with higher temperatures of the metal : at a dull red only traces 
of it are left. 

In contact with nickel, ethylene is decomposed into carbon and 
hydrogen, but the latter is taken up immediately by a portion of the 
ethylene to form ethane which is more and more broken down to 
methane at higher temperatures. The nickel is found diffused in the 
carbon that is formed." 

Propylene suffers an analogous destruction but more slowly and 
without the voluminous swelling of the metal. The decomposition is 
appreciable at 210^ and is dean at 350^. The escaping gas contains 
propylene, propane, ethylene, ethane, methane and hydrogen.^ 

All other unsaturated hydrocarbons give analogous results, e.g. the 

* Sabatibr and Sbndbrbns, Ann, Chim, Phy. (8), 4, 435 (1905). 

* Slater, /. Chem. Soe,, X09, 160 (1916). 

^* Sabatisb and Sbndxbidnb, Ann. Chim, Pky$, (8), 4, 435 (1906). 
u Sabatieb and Sbmdxbens, Compl, rend., 124, 616 and 1358 (1897). 
" Sabatobb and Sbmdbbbns, Compi. rend., 134, 1128 (1902). 



329 DECOMPOSITIONS OF HYDROCARBONS 916 

vapors of trimethyJrethylene give along with a deposit of carbon, the 
saturated hydrocarbon with the whole series of lower hydrocarbons. 

Cobalt acts in a similar manner but less actively than nickel. With 
ethylene at 360^ and even at 425^ there is slow carbonization without 
rapid swelling a^d much ethylene survives. 

Iron does not act till above 350^ and gives a still slower decompo- 
sition. 

PUxHnum (black or sponge) and reduced copper do not have any 
appreciable action on propylene or ethylene." 

913. Acetylene Hydrocarbons. Sindlar dehydrogenating actions, 
but less intense, are exercised by the finely divided metals on the 
aletylene hydrocarbons, especially acetylene. The action can be di- 
vided into two entirely distinct kinds, which coexist. One of these is 
easily observed with platinum or iron, the other particularly with cop- 
per, while nickel superimposes the two effects. 

914. First Kind of Reaction. Pure acetylene when heated with 
platinum to 150^, is rapidly decomposed into carbon and hydrogen : 
the heat evolved by this decomposition heats the metal to incandes- 
cence which accelerates the destruction giving rise to a great carbon- 
aceous swelling, and which causes the pol3anerization of the remaining 
acetylene into benzene, styrene, and hydrides of naphthalene and 
anthracene as in the celebrated synthesis of Berthelot. This phe- 
nomenon was observed by Moissan and Moureu;^^ it is complicated by 
an important consecutive action, which escaped these chemists but 
which Sabatier and Senderens have studied.^* 

The hydrogen resulting from the decomposition of one portion of 
the gas can act on another portion, in the presence of platinum, to 
form ethylene and ethane. The liquid collected is small in amoimt and 
is chiefly benzene. This is the composition by volume of the gases 
evolved : 

Acetylene 66.2% 

Benzene (vapor) 2.8 

Ethylene 25.4 

Ethane 0.6 

Hydrogen 5.0 

915. A much greater destructive activity belongs to reduced iron 
(obtained at about 450*^) which is raised by acetylene from room tem- 
perature to incandescence. If the tube containing the iron is not 
heated, the reaction ahnost stops with the local decomposition due to 

" Sabatibb and Sbndbbenb, Ann. Chim. Phys. (8), 4, 436 (1005). 

^* M0188AM and MouBSU, Compt, rend., laa, 1241 (1806). 

" Sabatikb and SBMDitBSNS, Compt. rend., 131, 40, 187 and 267 (1000). 



916 CATALYSIS IN ORGANIC CHEMISTRY 330 

the incandesoence, the formation of black voliuninoufi carbon in which 
the iron is disseminated and of brown liquids, almost entirely aromas- 
tic. The gases remaining are Uttle but surviving acetylene and hy- 
drogen saturated with benzene vapor. But if the entire iron tube is 
kept at above 180^, the hydrogenation of the acetylene is carried on 
by the metal beyond the incandescent portion so that little acetylene 
is left and the gas is only hydrogen, ethylene and ethane with the 
vapors of higher hydrocarbons. 

916. Second kind of Reaction. This is caused by copper. 

If a current of acetylene is passed over Ught copper (obtained by 
reduction at a low temperature) at 180^ the copper is seen to turn 
brown at once and the pressure diminishes greatly on account of the 
rapid condensation of the acetylene in contact with the metal. Some- 
times the current of acetylene which was 20 cc. per minute is entirely 
taken up for more than 20 minutes and then slowly begins to pass. 
At this moment the copper is seen to swell rapidly taking on a lighter 
tint of brown and soon filling the tube so as to stop the flow of gas. 

The condensed liquid is a mixture of unsaturated and aromatic 
hydrocarbons {benzene, styrene etc.), the presence of the styrene caus- 
ing partial soUdification after a time.^* The small amoimt of gas that 
passes out contains, with a small amoimt of acetylene, hydrogen, 
ethane and particularly the unsaturated hydrocarbons, ethylene, 
propylene and butylene, which constitute more than two thirds of it. 

The copper is found disseminated in the entire brown soUd mate- 
rial formed. If a small portion of this is placed as a layer in another 
tube and heated to 180-250^ in a current of acetylene, the material 
swells up, again filling the tube. One can start anew with a portion 
of this material and fill another tube. After three or four such swell- 
ings, a material is obtained which is no longer changed when heated 
in acetylene. This is a lighter or darker brown soUd which appears 
imder the microscope to be a thick felt of very fine filaments. It is 
light and fluffy and may be agglomerated into masses resembling 
tinder. It is a hydrocarbon of the emp3rrical formula CrHe in which 
is foimd diffused a Uttle copper (about 1.5%) which has caused its 
formation : this is cuprene,^'' Its composition is identical with that of 
the condensed hydrocarbon formed by the decomposition of bemyl 
chloride by metallic chlorides (880) or by the dehydration of benzyl 
alcohol (714), and is perhaps hexapJienyUcyclohexane, CeHe(C6H6)«.^* 

^* On account of polymerization of the styrene to a solid. — E. E. R. 

^^ Sabatibb and Sbndbrens, BvU, Soc, Chim, (3), az, 530 (1800). — Campt. 
rend,, 130, 250 (1000). — Sabatusb, Srd Congress on Acetylene, Paris, 1000, 345 
and 4ih Cong. Applied Chem,, Paris, 1000, 3, 134. 

" Sabatisb and Maumk, Ann. Chim. Pkys. (8), ao, 208 (1018). 



331 DECOMPOSITIONS OF HYDROCARBONS 918 

The formation of cuprene is doubtless due to the formation of an un- 
stable acetylide capable of reacting with acetylene to form a new con- 
densed molecule, thus : 

nCjHi + nCu - nCjCu + nHj 
and nCjCu + 6nCjHi - (CeHT)^ + nCu, 



ouprene regenerated 

The regenerated metal is capable of repeating the reaction indefi- 
nitely. The hydrogen set free combines with a portion of the acety- 
lene over the copper to give chiefly ethylene hydrocarbons. 

Compact copper, in sheet or wire, gives a similar formation when 
heated in acetylene to 200-^0^ and covers itself with a brown coat- 
ing which becomes more yellow as its thickness increases. 

917. Supexposition of the Two Kinds of Reaction. If over a layer 
of reduced copper heated at its middle portion to above 250^ a rapid 
current of acetylene be passed, incandescence accompanied by intense 
swelling is observed at this point and there is simultaneous production 
of carbon and of cuprene formed by the superposition of the two 
reactions. 

918. Reduced nickel usually causes both reactions. If the re- 
duced nickel is entirely freed from the hydrogen absorbed by its 
particles, it no longer becomes spontaneously incandescent in acetylene 
and can be heated to 150^ before it causes a reaction. It is only above 
180^, that a slow reaction takes place, without incandescence, and this 
reaction remains thus if the passage of the gas is not too rapid. The 
metal turns black and swells a little, covering itself with a solid 
brownish fibrous silky hydrocarbon which suggest cuprene; but this 
formation is slow and if one tries to accelerate it by passing the acely- 
lene more rapidly or by elevating the temperature, incandescence 
appears bringing rapid decomposition with charring. 

Usually when acetylene is passed over a layer of recently reduced, 
nickel without precautions, there is inmiediate spontaneous incandes- 
cence, brought on by the occluded hydrogen, and carbonizing decom- 
position takes place always followed by the hydrogenation of the 
acetylene and of a part of the aromatic hydrocarbons resulting from 
the incandescence because the nickel is capable of effecting such hy- 
drogenations. 

Summing up, nickel acting on acetylene at 180^ produces a triple 
effect: 

1st. Rapid decomposition into carbon and hydrogen with poly- 
merization to aromatic hydrocarbons. 

2nd. Slow condensation into a solid hydrocarbon doubtless identi- 
cal with cuprene. 



919 CATALYSIS IN ORGANIC CHEMISTRY 332 

3rd. Hydrogenation of the acetylene and of the aromatic hydro- 
carbons with production of aliphatic, unsaturated and cyclo-aliphatic 
hydrocarbons. 

With a tube that is not externally heated, where the incandescence 
is intense and localized at a single point, the first effect is the greatest, 
the velocity of the gas rendering the subsequent hydrogenation 
unimportant. These are the conditions studied by Moissan and 
Moureu. 

919. With cobalt quite free from nickel and reduced from oxide at 
below 350^, incandescence is not obtained, starting with the tube 
cold, but is readily started by heating some point on the tube, and is 
easily maintained if the tube is heated to 200^. The action is inter- 
mediate between that of iron and that of nickel. The tube is filled 
with a black mass consisting of carbon in which the cobalt is diffused 
and traces of a hydrocarbon analogous to cuprene can be seen.^* 

920. The effects of nickel, iron, cobalt and copper are much less 
intense when these metals are employed in the form of sheets and have 
appeared to many observers negligible even up to 600^. On the con- 
trary magnesium powder acting at 600^ on methane, ethane, ethylene 
and acetylene causes a 95% decomposition. Aluminum powder, at 
near the fusion point of the metal, causes a total decomposition while, 
platinum decomposes only 80%.*® 

Hexane, imder high pressure, is attacked energetically at 650-700^ 
in an iron tube in the presence of aluminaJ^^ 

921. Cyclic Hydrocarbons. As has been said above (640), the 
hydro-cyclic hydrocarbons in contact with finely divided metals form 
the corresponding aromatic hydrocarbons by loss of hydrogen; but 
the cyclic hydrocarbons, benxene, its homologs, naphthalene, anthra- 
cene etc. are themselves attacked, and tend to be resolved into CHs 
and CH groups like those furnished by the aliphatic hydrocarbons. 
Metallic oxides also can catalyze decompositions of this sort. 

Finely divided nickel, iron and cobalt act energetically above 400^ 
and especially at a dull red heat, on the hydro-cyclic hydrocarbons, 
among which are the terpenes, and cause, along with dehydrogenations 
which take place at lower temperatures (640), decompositions more 
and more serious as the temperature is raised, and accompanied by 
carbonaceous deposits which increase at the same time. The charring 
is less intense with copper. 

The aromatic hydrocarbons, benzene and its homologs, are much 

» Sabatibb and Sendbbbns, Ann, Chim. Phys, (8), 4, 430 (1905). 
» EusNETZOW, BerichU, 40, 2871 (1907). 

^ Ipatibf and Dovgblevich, /. R\a9ian PhyB. Chem, Soc,, 43, 1431 (1911); 
C. A., 6, 736 (1912). 



333 DECOMPOSITIONS OP HYDROCARBONS 924 

less affected by the action of finely divided metals than when they are 
acted on in the nascent state, that is when they are being formed by 
the dehydrogenation of cydohexane or terpene hydrocarbons. 

922. The Case of Pinene. The action of heat on pinene when its 
vapors are passed through a red hot tube has been described above 
(909). The tube being of iron and sometimes filled with broken pum- 
ice or porcelain the peculiar influence of the metal or of the filling 
may enter into the reaction. 

By passing these vapors over very light finely divided copper (59) , 
in a glass tube heated to 600-30^, a rapid evolution of gas of high 
illiuninating power consisting of hydrogen charged with the vapors of 
lower hydrocarbons, is obtained. By conducting the operation very 
slowly, 100 cc. of pinene gave 81 cc. of condensate which contained : 



13.3 cc. passing over below 95 
27.0 cc. passing over from 95^ to 150 

31.4 cc. passing over from 150^ to 185 
9.3 cc. passing over above 185 



o 

9 
o 

o 



Treatment with sulphuric acid, which dissolves the terpenes and 
the ethylenic and di-ethylenic hydrocarbons, reduced the volume to 
31.5 cc. of hydrocarbons ahnost entirely nitrifiable and consisting of 
about 19 cc. cymene and methyl-ethyl-benzene, 10 cc. m. xylene and 
toluene and a small amount of benzene. In the most volatile portion 
of the hydrocarbons is found some isoprene, hardly more than 2 cc. 
The terpenes remaining in the product have no effect on polarized 
light. 

923. Reduced nickel acts more violently than copper at 600^ and 
causes intense carbonization in consequence of its destructive action 
on ethylenic and di-ethylenic hydrocarbons (912). The gas is richer 
in hydrogen, the liquids condensed are less and contain a considerable 
proportion of saturated hydrocarbons resulting from the hydrogenat- 
ing action of the metal on the unsaturated hydrocarbons and un- 
attacked by either sulphuric or nitric add.^ 

Reactions carried out in the Presence of Hydrogen 

924. The decompositions of the hydrocarbons by the metals cor- 
respond to an elimination of hydrogen of which a portion is utilized 
for hydrogenating the fragments. It seemed probable that the pres- 
ence of hydrogen with the hydrocarbon molecules would stabilize 
them or would favor the hydrogenation of the fragments resulting 
from their decomposition. The stabilization is actually realized in the 

** Sabatibb, Mauhx and Gaudion, Campt. rend,, i68, 826 (1919). 



925 CATALYSIS IN ORGANIC CHEMISTRY 334 

case of the cyclohexane hydrocarboDS which are preserved to a great 
extent (640), in the case of the aromatic hydrocarbons derived from 
the terpenes (644). Hydrogenation carried out at temperatures at 
which the hydrocarbons are broken up would necessarily lead to the 
hydrogenation of the fragments that would be formed in the absence 
of the hydrogen. 

925. Acetylene. We have seen (423) that the direct hydrogena- 
tion of acetylene, carried out over cold nickel or at a low temperature, 
gives ethane accompanied by a certain amoimt of higher aliphatic 
hydrocarbons, both gaseous and liquid: the reason for the formation 
of these by-products being the breaking up of the molecule HO * OH, 
which takes place at near room temperature, thereby hberating the 
CH groups which are hydrogenated to methane, CH4, or to the groups 
CHt and CHs, the groups CHs, CHt and CH being able to unite in 
various ways to give, in the cold, more or less complex aliphatic hy- 
drocarbons. By operating continuously for 24 hoiu^ with nickel 
maintained at 200^, Sabatier and Senderens condensed about 20 cc. of 
a clear yellow liquid with a splendid fluorescence and an odor quite 
similar to that of rectified petroleum. It began to boil at about 45^ and 
half of it passed over below 150^, while at 250° there remained a small 
quantity of very fluorescent orange yellow liquid, certainly containing 
polycyclic hydrocarbons. The original liquid had a density of 0.791 
at 0° and was slightly attacked by the nitro-sulphuric acid mixture 
which extracted a small amount of aromatic hydrocarbons. The re- 
maining oil had a density of 0.753 at 0° and was composed almost 
entirely of aliphatic hydrocarbons (pentane, hexane, heptane, octane, 
nonane, decane, undecane etc.) which were associated in the original 
product with unsaturated hydrocarbons, soluble in slightly diluted 
sulphuric add, and with traces of aromatic hydrocarbons. The com- 
position, odor, density and fluorescence class this liquid with Penn^ 
sylvania petroleums, 

926. If through a tube containing reduced nickel and kept be- 
tween 200 and 300*^, a rapid current of piu^ acetylene is passed, with- 
out hydrogen, a lively incandescence is obtained on account of the 
decomposition of the acetylene into carbon and hydrogen (918). A 
portion of the acetylene thus carried to a high temperature condenses 
to benzene and other aromatic hydrocarbons according to the reaction 
discovered by Berthelot; another portion breaks up into CH groups 
which can be hydrogenated along with the aromatic hydrocarbons by 
the portion of the nickel layer which remains at 200-300**. In the 
receiver is collected a considerable amount of liquid, greenish by re- 
flected light, reddish by transmitted, the appearance of which greatly 



335 DECOMPOSITIONS OF HYDROCARBONS 930 

resembles crude petroleum. If this liquid is hydrogenated directly 
over nickel at 200^ a colorless liquid is obtained which is only slightly 
attacked by the nitro-sulphuric acid reagent and which, on fractiona- 
tion, gives a whole series of liquids of densities similar to those of the 
corresponding fraction of Caucasian petroleum. The chief constituents, 
as in the petroleum fractions, are the polymeihylene hydrocarbons 
resulting from the hydrogenation of the aromatic hydrocarbons formed 
by the incandescence. As in the Caucasian petroleum there are cer- 
tain amoimts of aliphatic hydrocarbons resulting from the hydrogena- 
tion of the CH groups which are set free and then reimited in various 
fashions. 

927. By causing incandescence in mixtures of acetylene and hy- 
drogen, the proportion of the aliphatic hydrocarbons is increased and 
the poly-methylenes diminished and intermediate pefyroleum^ are 
obtained. 

If the hydrogenation following the incandescence takes place at 
about 300**, the cyclohexane hydrocarbons are formed only incom- 
pletely and are accompanied by certain proportions of imtransformed 
aromatic hydrocarbons : we have Oalidan petroleum, 

928. Analogous reaction can be effected by finely divided cobalt 
and to a certain extent by iron. Sabatier and Senderens, who found 
out the above facts, have based on them a simple theory of the gene- 
sis of natural petroleum. There are doubtless far down in the earth's 
crust large masses of alkaline and alkaline earth metals as well as of 
the carbides of these metals. Water penetrating through fissures in the 
rocks and coming in contact with these materials will evolve hydro- 
gen and acetylene, in proportions which will doubtless vary greatly. 

If the hydrogen is in large excess, the gaseous mixtiu^, coming in 
contact with nickel, cobalt or iron disseminated in adjacent rocks at 
temperatures which may be lower than 200**, gives rise to American 
petroleum and at the same time to large quantities of combustible 
gases in whch are found, as in the natural gas of the Pittsburgh dis- 
trict, much methane, ethane and free hydrogen.^ 

Use of Anhydrous Aluminum Chloride 

929. Anhydrous aluminum chloride heated with aliphatic hydro- 
carbons, tends to decompose them into lower and higher hydrocarbons. 
Amylene gives methane at the same time as hexane and still more con- 
densed hydrocarbons.*^ 

930. More important and more regular effects are observed with 

*■ Sabatdbr and Sbndebbns, Ann. Chim, Phya. (8), 4, 446 (1906). — SASATiBBy 
Rev. Mais, i, 267 (1906). 

M Abchan, Annalen, 334, 1 (1902). 



931 CATALYSIS IN ORGANIC CHMEISTRY 336 

aramalic hydrocarbons, as has been stated above (887), tending to their 
degradation and building up at the same time. EihyJrbenzene heated 
with aluminum chloride is degraded to benzene, while diethyl-benzene 
is formed to compensate (888). 

A xylene (in which the meta predominated) boiled for 5 minutes 
with 2 % anhydrous aluminum chloride in an apparatus with a me- 
chanical stirrer gave 29% of hydrocarbons boiling below 135^. Pro- 
longed boiling raised the yield only to 34 %, nor does increasing the 
amount of the chloride increase it sensibly. Benzene is formed chiefly 
with a little toluene. The proportion of toluene is no better when the 
operation is carried on under 18 atmospheres pressure.'* 

Cymene heated with a third of its weight of aluminum chloride 
gives a mixture which contains : 2 % benzene, 42 % toluene, and 7 % 
xylene (chiefly meta) with a little di^opropyl-bemene and methylrdi- 
isopropyJrbenzene, increasing the amount of the catalyst increases the 
amount of the benzene and decreases the toluene.'* 

931. Naphthalene heated in an autoclave at 330^ under 10 atmos- 
pheres pressiure, for 20 minutes with 4 % anhydrous ahiminum chloride 
gives, along with a carbonaceous and tarry material, 32 % of a liquid 
hydrocarbon of which about half is dihydro-naphthalene resulting from 
the hydrogenation of one part of the naphthalene at the expense of 
another.*'^ 

Under the action of anhydrous aluminum chloride, pinene gives 
penlane and its homologs as well as cyclohexene hydrocarbons.'* 

Application to the Treatment of Petroleums 

932. The use of catalysts enables us to improve greatly the opera- 
tion of cracking (906) for the purpose of increasing the volatile portion 
of petroleum, since it lowers greatly the temperature at which the 
reaction takes place thus permitting the siuidval of molecules result- 
ing from the decomposition which would otherwise be attacked at the 
higher temperatures. 

If over finely divided metals, such as powdered iron or reduced 
copper, maintained at a temperature between 400^ and a dull red, the 
vapors of a crude petroleiun (from any source) or of petrolemn pre- 
viously stripped of its gasoline, there is partial decomposition into a 
mixture of hydrogen and gaseous hydrocarbons and liquids of which a 
considerable proportion distils below 150^ and may be separated. 

** F. Fischer and Niggbmann, BerichU, 49, 1475 (1916). 
*• ScHOBGER, J. Amer. Chem, 80c,, 39, 2671 (1917). 
" F. Fischer, Berichte, 49, 262 (1916). 
^ Stbinkopf and Frbttnd, Berichie, 47, 411 (1914). 



337 DECOMPOSITIONS OF HYDROCARBONS 933 

When the residue is again submitted to the action of finely divided 
metalSi a new amount of volatile liquids is formed, and so on. 

The gases evolved are quite abundant and are composed of satu- 
rated and unsaturated hydrocarbons having high calorific and illum- 
inating power. 

Iron has the inconvenience that it causes an abundant deposit of 
carbon on its surface. Copper causes much less of this but requires a 
higher temperature, near to 600^; temperatures below 550^ give poor 
results while above 800^ there is intense carbonization with diminu- 
tion of the yield of gasoline. 

Thus starting with an American petroleum containing nothing 
boiling below 150^, by a single passage over copper at 600^, 1 1. gave 
^5 cc. gasoline boiling below 150^. At the same time 120 1. of gas 
was evolved with high illmninating power and having a heating power 
of 15,000 calories per cu. m. 

After some time the copper becomes too much fouled with carbon- 
aceous materials and does not have sujBGicient activity. In order to 
regenerate it all that is necessary is to pass over it a current of steam 
which causes the carbon to disappear without altering the metal while 
producing water gas which may be used for heating the apparatus. 

The liquids thus obtained are composed in part of saturated and 
aromatic hydrocarbons and in part of hydrocarbons containing one or 
two double bonds. These are oxidisable and polymerizable and have a 
disagreeable odor. In the experiment cited above their proportion 
was 40%. 

In order to transform them into saturated compounds without 
disagreeable odors it is sujBGicient to hydrogenate their vapors in the 
presence of finely divided metals (particularly reduced nickel) between 
150^ and 300^. A hydrocarbon is thus obtained that may be used as 
gasoline. Furthermore, the two phases of the process can be com- 
bined so as to transform continously a crude petroleum or petroleum 
residue into gasolinie, of which as high as 75% may be obtained.'* 

033. Numerous patents have been taken out for processes of this 
sort. One proposes to use finely divided metals at 600^ under 6 at- 
mospheres pressure.*^ 

In another patent, the gas issuing from the catalytic cracking is 
charged with ammonia and thus modified is used to carry along the 
vapors of the hydrocarbon over metal oxides which can be reduced to 
the metal. The nascent hydrogen set free by the decomposition of the 
ammonia by the metal, saturates the hydrocarbons and diminishes the 

** Sabatieb, French patent, 400,141, May, 1009. 

M Hall, Englieh patent, 17,121, of 1913; /. 8. C. /., 53. 1149 (1914). 



9S4 CATALYSIS IN ORGANIC CHEMISTRY 338 

amount of the carbonaceous deposits. By this process gaiioline free 
from sulphur is obtained even from Mexican petroleum containing 5 % 
of sulphur.** 

934. Catalytic oxides {tUania, alumina^ and zinc oxide) can also 
be utilized for such transformations, particularly for changing Russian 
cyclohexane petroleimis into aromatic hydrocarbons {benzene^ toluene 
and homologs). A benzine from Baku (98 to 102**) gave 30% of aro- 
matic hydrocarbons of which over half was toluene. 

The use of iron retorts is to be avoided on account of the intense 
carbonization which this metal causes and the rapid deterioration 
which results therefrom." 

935. Aluminum chloride enables us to carry out analogous re- 
actions at much lower temperatures (929). 

Petroleum freed from water and gasoline is heated 24 to 48 hours 
with dry aluminum chloride. The products obtained are almost en- 
tirely saturated and it is unnecessary to treat them with sulphuric 
add, washing with soda and then with water being sufficient to get 
rid of the hydrogen sulphide. The aluminum chloride is regenerated 
by submitting the residual coke to a current of chlorine at a red heat. 
The yield of gasoline from Oklahoma petroleum, which gives only 
12.5% by the ordinary cracking process, is raised to 34.8% by this 
method.** 

936. Iron chloridesi although less active, may be substituted for 
the aluminum chloride, and with Russian oils, very poor in gasoline, 
a certain amount of hydrocarbons passing over from 40^ to 140^ is 
obtained^ Of this about 35 % is hexane and heptane while the rest is 
chiefly 7 and 8 carbon cyclic hydrocarbons. Heavy hydrocarbons the 
consistence of which resembles asphalt, are produced at the same 
time.** 

u Valft and Lucas, EnglWi paterU 20,470 of 1913 and 2,838 of 1914; /. Soc. 
Chem. /nd., 34* 71 (1915). 

a Zblinski, J. Russian Phya. Chem. Soc., 47, 1807 (1915). 

" McAfee, J. Ind. Eng. Chem., 7, 737 (1915). 

** PicTBT and Lbrcztnbka, BvJU. Soc. Chim. (4), 19 (1916). 



SUPPLEMENT TO CHAPTERS XI AND XH 
HTDR06ENATI0N OF LIQUID FATS 

937. The liquid fats, oils of various origins, contain along with the 
neutral glycerine esters of the saturated acids, (CnH^Os,) palmitic, 
margariCy stearic, arachidic etc., a considerable proportion of the 
glycerine esters of the unsaturated adds, either ethylenic acids, 
(CnHsn-^Os,) hypogalc, ol^, elaldic, erudc etc., or diethylenic, 
(CHtn^Os,) as linol&Lc, or unsaturated hydroxy as ridaoUiic, or still 
more unsaturated acids as linolenic, CuHmOs and dupadonic, CisHaOs. 
The unsaturated acids and their glycerine esters have much lower 
melting points than the corresponding satiurated compounds, thus : 

Stearic acid, CisHmOi melts at 71^ 

Oleic add, CuHmOs melts at 14'' 

Ricinoleic acid, CuHmOi melts at 26^ 

linolelc add, CisHnOi melts below -18^. 

Stearine, or glycerine tristearate, melts at 71.5^ while oleine, or 
glycerine trioleate, is liquid at the ordinary temperature. In some 
cases these unsaturated compounds have disagreeable odors. The 
presence of clupadanic acid is responsible for the repulsive odor of fish 
oils. 

938. The absorption of iodine by fats gives an exact measure of 
the amounts of unsaturated adds that enter into their constitution. 

By the term iodine number we mean the amount of iodine ab- 
sorbed by 100 parts of the fat.^ 

The following table gives the average value of the iodine number 
for a number of different fats: 

Cocoa butter 36 

Mutton or beef tallow 35 to 47 

Hog lard 44 to 70 

Goose fat 77 

OUve oU 82 

Colaa oil 100 

1 HtoL, DingUr^s PolyUch. /., 253, 281 (1884). 

339 



S39 CATALYBIS IN ORGANIC CHEMISTRY 340 

Almond oil 98 

Castor ofl 84 f 

Peanut oil 97 

Cottonseed oil 109 

Sesame oil 108 

Poppy seed oil 133 to 158 

Whale oil 127 

Cod Uver oil 140 to 180 

Linseed oil 180 

Clupadonie add 365 to 370. 

939. By adding hydrogen and thereby transforming imsaturated 
glyoerides into saturated, the bad odors of certain oils (fish and oo- 
coanut) disappear and the melting points are greatly raised. 

When applied to the oils themselves, hydrogenation changes them 
into solid fats, i.e. more and more solid the more the ofeine is trans- 
formed into stearins. 

Sabatier and Senderens showed between 1897 and 1902 that hy- 
drogen is easily added to ethylene bonds in the presence of reduced 
nickel at temperatures below 250° and it was desired to apply this 
method to the hydrogenation of the liquid fatty acids or to the oUs 
themselves. It is possible by dragging the vapors of ol^ acid by a 
violent current of hydrogen over nickel at 280° to transform it com- 
pletely into stearic acid. A column of reduced copper can effect the 
same reaction at 300° and in this case the hydrogen may be replaced 
by water gas.* 

In the patents of Bedford/ the fatty material vaporized in hydro- 
gen under reduced pressure is hydrogenated while traversing a vertical 
cylinder filled with nickeled pmnice heated to 200°, but the lowering 
of the pressure of the gas is imfavorable to its fixation. 

940. The difiSculty of volatilizing the liquid fatty acids and the 
practical impossibility of volatilizing the oils themselves led to the 
abandonment of the reaction on the vapors and to attempts to effect 
it in the liquid material. The patent of Norman of 1903 compre- 
hended hydrogenation of the vapor and of the liquid.^ 

It is to hydrogenation in the liquid medium that almost all of the 
very numerous patents applying to this important industrial problem 
relate : more than 200 have been taken out on the choice, preparation 
and method of using catal3rst8 or for apparatus. 

< Sabatibb, Frtnch patent, 394,957 (1907). 

* Bbdfobd and Williahb, English patent, 9,112 of 1908. — Bedford, 17. S. 
patent, 949,954 (1910). 

« NoBMAN, Engliah patent, 1,515 of 1903. 



341 HYDROGEN OF LIQUID FATS 943 

941. Catalysts* Nickel is most frequently employed being used 
alone in the finely divided state as is obtained by the reduction of the 
oxide with hydrogen, or more commonly incorporated with an inert 
material intended to disseminate it and to increase the useful surface 
of contact with the hydrogen and oil. For this purpose have been 
used nickeled pumice,^ kieselguhr, or infusorial earth, impregnated 
with nickel*, nickeled ad)€stos'', and wood charcoal impregnated with 
nickel.^ The method of incorporating the nickel with the carrier may 
vary : for example, the nickel is dissolved in sulphuric add and double 
its weight of siliceous material is added (pmnice, kaolin, asbestos etc.) ; 
the metal is precipitated as the carbonate which is calcined to form 
the oxide which is thus distributed over every fragment of the porous 
material, and the oxide is reduced by hydrogen at 350^.* 

042. It has been suggested to use the finely divided nickel 
formed in the decomposition of nickel carbonyl by heat. Finely di- 
vided nickel is kept suspended in oil at above 180^ and a current of 
carbon monoxide or of water gas is passed through. This transforms 
the metal into nickel carbonyl which immediately breaks down into 
carbon dioxide, carbon and finely divided nickel which remains sus- 
pended in the liquid and is ready to realize its hydrogenation at a 
somewhat higher temperature, around 22(M0^." Practically the nickel 
thus formed may be only 0.1 % of the oil to be hydrogenated. 

It has been proposed to impregnate pumice or kieselguhr with 
nidcel carhonyl and then heat it to liberate the metal which should be 
perfectly spread over the porous material : the catalyst thus prepared 
is incorporated in the oil to be treated without coming in contact with 
the air." 

943. The substitution of nickel oxides for metallic nickel has put 
over against existing patents, other patents which could not be of 
value if the oxide does not act until after it has been reduced to the 
metal, as various investigations seem to have established (598). 

• NoBMAN, EngUsh patent, 1,515 of 1903. — Bedford and WiiUAifS, Bnglish 
patent, 0,142 of 1908. — Ebdmakn, German patents, 211,660, C, 1910 (1),1006, and 
222,800 (1007), C. A,, 4, 2715 (1010). 

• Eatsbb, U. S. patents, 1,004,035 and 1,008,474 (1011), /. S. C. L, 30, 1266 
and 1461 (1011). — Wn^nBCHXWiTCH, French patent, 426,343 (1010), J. S. C. /., 
30, 066 (1011).— Cbossfibld and Mabkbl, French paient, 435,240 (1011), /. S. CJ., 
3* 346 (1012). 

' ScHWOBBXB, Oerman patent, 100,000 (1006)). 

< Eujs, U. S. patent, 1,060,673, (1013), C. A,, 7, 2132 (1013). — Ittneb, Mat 
Qraeees, 19x8, 4064/ 

• WiLBuacmBwrrcH, Englieh patent, 15,430 of 1011, /. S. C. /., 30, 1170 (1011) 
1* Shuxoit, German patent, 241,823 (1010), C, 19x3 (1), 175. 

^^ ScHiCHT, Mat fgrasaee, 19x69 4634. 



9M CATALYSIS IN ORGANIC CHEMISTRY 342 

This substitution, inspired by the work of Ipatief (584) , has been 
advised by Bedford and Erdman, who believe that the most active 
catalyst is a sub-oxide such as NtO,^ and has been frequently applied 
to the hydrogenation of oils.^ ^* 

944. Various salts of nickel have been proposed to replace the 
oxide as catalyst. Nickel borate recommended by Schdnfeld ^* as being 
very active, has been found by other chemists absolutely useless unless 
broken down to the oxide by a temperature of above 260**, the presence 
of the boric acid appearing to be unfavorable.^* 

The nickel salts of organic acids, acetate, lactate, and especially the 
formate have shown themselves useful." The product produced by 
heating nickel formate in a current of nitrogen has been advised. ^^ 

945. The other common metals near to nickel, iron, cobalt and 
copper have been rarely used although they figure along with nickel in 
a large number of patents.^* The same is true of platinum on account 
of its high price which is not compensated for by any special activity. 

946. PalUdhmi on the contrary, has been recommended as a cata- 
lyst for oils in spite of its high cost because of its remarkable activity, 
I part of metal effecting the hydrogenation of 10,000 ^ parts of oil be- 
low 100^. It is advantageously employed at about 80^ under 2 or 4 
atmospheres of hydrogen.*^ It is best to use the palladium precipi- 
tated on an inert carrier, either animal charcoal or a metallic oxide or 

" Bedford and Ebdmann, /. prdki, Chem. (2), 87, 425 (1013). 

u Bbdfobd and Wiluams, French patents, 418,355 (1910); 436,295 (1911); 
/. 5. C. /., 31, 444 (1912). —English patent, 29,612 of 1910, J, S, C. I., $1, 398 
(1912). — U. 8. patent, 1,026,339 (1912), J. S. C. I., 31, 593 (1912).— Bbdvosd and 
Ebdmann, French patent, 451,155 (1912),— /. 8. C. /., $2^ 602 (1913). 

^^ The exact comparative experiments of WillstXtter and WALDSCHHiDiy 
Lbitz {Berichte, 54, 131, (1921)) go far towards proving that nickel is entirely in- 
active unless it contains some oxygen. Using 0.2 g. nickel in 20 cc. water with 
1 g. sodium cinnamate, no hydrogen was taken up in 1 hour at 60^ but the 
catalyst was activated by shaking with oxygen for 15 minutes. A number of 
simikr experiments are cited. A quantitative experiment showed that the 
amount of oxygen absorbed by a sample of nickel, exposed to the air, was not 
weighable yet the nickel was activated by this exposure. — E. E. R. 

» SchOnpbld, ZeU. f. angew. Chem,, 27 (2), 601 (1914), C. A., 8, 3868 (1914). 

^* Erdmann and Rack, Zeit, /. angew. Chem,, a8, 220 (1915), C. A., 9, 1255 
(1915). 

17 WniMSR and Hioqins, French patent, 441,097 (1912), /. 8. C. /., 31, 826 
(1912). 

1* HiGGiNB, Mat. grasses, ZQXTi 4760. 

" Norman, English patent, 1,515 of 1903, J. 8, C. /., 231 26 (1904). — Wil- 
BUSCHRWiTCH, French patent, 426,343 (1910), /. 8. C. /., 30, 966 (1911). 

*^ Hydrogenation of cottonseed oil may be carried on at 180** with this propor- 
tion of nickel on a carrier. — E. E. R. 

" Day, U. 8. patent, 826,089 (1906), J. 5. C. /., aSi 1036 (1906). 



343 HYDROGEN OF LIQUID PATS 949 

carbonate or magnesium or nickel, the use for this purpose of iron, 
lead, zinc or aluminum being unfavorable.^ 

The chief disadvantage in the use of palladium is its excessive cost 
since some loss of metal is inevitable, the cost according to experience 
amounting to 1.60 francs per 100 kg. oil treated. 

947. Life of Catalysts. Certain substances when found in even 
small amounts in the oils, paralyze the activity of catalysts and do 
not take long to render them inactive (112). The most to be feared 
in the hydrogenation of oils are sulphur compounds. 

Hydrogen sulphide immediately renders inactive 100 times its 
weight of nickel and pulverized avlphitr is half as effective. The action 
is less rapid with the same proportion of sodium sulphide. On the 
contrary, sulphates, sodium nitrate, and nickel chloride have no harm- 
ful effect. Free chlorine kills the nickel instantly.**** 

In contact with fish oil and whale oil the catalyst is quickly 
killed; the toxic material is fixed by the metal since if a fresh cata- 
lyst is added hydrogenation takes place. Consequently a practical 
method of purification of these oils is to agitate them with a spent 
catal3r8t which abstracts the harmful substances. 

948. Oils frequently contain free fatty acids which attack the 
nickel to the detriment of its catalytic activity. Hence it is best to 
neutralize them by agitation with pulverized calcium carbonate or with 
a small amount of dilute cold sodium carbonate solution. The neutral 
oil thus obtained may be effectively freed from its toxic materials by 
agitating it hot with freshly precipitated cupric hydroxide.*^ 

949. The presence of moisture in the oil or in the hydrogen can 
lead to a certain amount of saponification at the elevated tempera- 
ture at which the reaction is carried out, hence it is important to 
avoid the presence of water and to dry the gas before using it, e.g., by 
refrigeration to -20**.** 

» VBBBiNiaTB Chxm. Wbrkx, Oerman patent, 236,488 (1010), C. ii., 5, 3633 
(1911). — French paUnta, 427,720 and 434,027 (1011), J. S. C, /., 30, 1022 and 
31,346 (1912), — English patent, 18,642 of 1011, C. A., 7, 666 (1013). 

*■ MooRE, RiCHTBB, and Absdsl, /. Ind, Eng, Chem,, 9, 461 (1017). 

^ It is suggested by WillstIttbb and WALDScmoDT-LsiTZ (Berichte, 54, 127. 
(1021), that the pouBoning of catalysts, by certain substances, at least, may be due 
to the fact that they deprive the catalysts of their oxygen content and thereby 
render them inactive. They show that thiophene removes the oxygen from plat- 
inum bhick. In an experiment in which 1.0 g. bensene was being hydrogenated 
in acetic acid solution by means of 0.6 g. platinum black, 1.6 mg. thiophene was 
added whereby the activity of the catalyst was completely destroyed. The cata- 
lyst recovered 87 % of its original activity by treatment with oxygen for 2 hours. 
— ~ £• £• XV. 

» Ellis and Wells, Mat. grasses, X9X7» 4760. 

^ Soc. DB Stbabim. bt Savon, db Lton, French paJbsnt, 486,414 (1017). 



960 CATALYSIS IN ORGANIC CHEMISTRY 344 

950. Nickel catalysts that have been rendered inactive by long 
use are regenerated by degreasing and treating with nitric acid and 
calcining the nitrated material thus obtained. 

951. Amount of Catalyst The weight of catalyst can vary much 
according to the work it has to accomplish. The rapidity of the re- 
action is nearly proportional to the amount of catalyst used. It is 
usually best not to cut down the amount of the catalyst since it is 
convenient to shorten the time of the hydrogenation as much as pos- 
sible. Usually 2 or 3 % of nickel distributed on an inert material is 
employed. With palladium the amount of catalyst may be much 
smaller.^ 

952. Temperatures. The temperatures most frequently employed 
for hydrogenations with nickel are around 180^ but may sometimes be 
as low as 150^ and are frequently raised to 200-50^ especially when 
the oxide is used. 

Much lower temperatures sujQice with palladium, usually 80 to 
100°. 

Elevation of temperature increases the speed of the reaction 
greatly. In the neighborhood of 170-^** with nickel, raising the tem- 
perature 10° increases the velocity about 20%.'* 

953. Hydrogen. The hydrogen for hydrogenations may be 
prepared electrolytically or may be produced as a by-product in the 
manufacture of caustic soda. 

It can also be obtained by the action of steam on incandescent 
coke, the water gas thus formed, after absorption of the carbon di- 
oxide, being partially liquefied to eliminate the carbon monoxide. But 
it is more frequently prepared by the decomposition of water by me- 
tallic iron, the iron oxide so formed being reduced at a red heat by 
water gas. 

This decomposition can take place at a red heat alternating with 
the reduction of the iron oxide which is thus formed; but under these 
conditions it is difficult to avoid the presence of a certain amount of 
carbon monos^de which it is important not to admit in appreciable 
amount. 

Amounts of 0.25 to 2% of carbon monoxide produce a serious 
diminution in the activity of the catalyst; 6 or 8% prevent any hy- 
drogenation by the nickel either by forming a deposit of carbon which 
covers the catalyst (614), or because the carbon monoxide tinms the 
catalytic activity of the nickel to its own use in transforming itself 

*' Good results on cottonseed oil may be obtained with 0.1 % of nickel dis- 
tributed on 10 parts of carrier. — £. E. R. 

** MooBB, RiCHTBR and Van Absdbl, /. Jnd. Eng. Chem., 9, 461 (1917). — 
Mai. grasses, 19x8, 5018. 



346 HYDROGEN OP LIQUID FATS 

to methane.'* This toidcity of carbon monoxide is all the more pe- 
culiar since nickel carbonyl has no harmful effect when it is sent into 
the oil with the hydrogen, even in large amount, and since the nickel 
resulting from its decomposition is, up to a certain limit, superior to 
reduced nickel.** 

The result is that vxjUer gas containing about equal volumes of hy- 
drogen and carbon monoxide with a little carbon dioxide and nitrogen, 
which can give good results with copper as a catalyst (515), is pro- 
scribed in the hydrogenation of oils over nickel. 

954. According to Bergius, the formation of hydrogen by water 
and iron can be very advantageously carried out by operating with 
water kept in the liquid form by high pressures. By working under 
300 atmospheres at 300-40^, the reaction : 

3Fe + 4HsO - 4Hs + FeiOi. 

takes place completely and can be greatly accelerated by the presence 
of sodium chloride or ferrous chloride along with metallic copper. 
Under exactly the same experimental conditions, the amounts of hy- 
drogen evolved per hour were : 

Iron and water alone at 300'' 230 cc. 

Iron, water and FeCU at 300^ 1390 

Iron, water, FeCU and Cu at 300** 1930 

Iron, water, FeCU and Cu at 340** 3450 

An apparatus holding 45 1. can produce 102 cu. m. per day. The 
iron oxide obtained is in fine powder and easy to reduce to metallic 
iron by water gas. 

The hydrogen thus prepared is very pure since the iron carbides 
and sulphides which are in the iron are not attacked by liquid water. 
The hydrogen evolved under a pressure of 300 atmospheres can be 
stored in steel cylinders without further compression.'^ 

955. The volume of hydrogen required for hydrogenation varies 
with the proportion and nature of the unsaturated adds which enter 
into the composition of the oils. 

For pure oleic acid about 79 cu. m. per 100 k. of acid are required 
while linol^ add requires twice and clupadonic add four times this 
amount. 

*• Maxtbd, Trans. Faraday Soc., Z3» 36 (1918). 
^ Maxtbd, Trans. Faraday 8oe., Z3» 201 (1918). 

» Bbbgiub, /. See. Chsm. Ind., 3a» 463 (1913). — Qerman patents, 254,593 and 
286,961. 



066 CATALYSIS IN ORGANIC CHEMISTRY 346 

The corresponding glyoerides require somewhat less, about 76 cu. 
m. for oleine. The amount required by an oil is proportional to its 
iodine number; lineeed oil requires 150 cu. m. per 1000 k. " 

956. Pressure. It is advantageous to operate under pressures 
higher than atmospheric, the velocity of the hydrogenation being, at 
least up to a certain limit, proportional to the pressure of the hydro- 
gen. In practice, pressures of 2 to 15 atmospheres are used. 

957. Apparatus. A large number of forms of apparatus, many of 
which differ only in details, have been devised for the hydrogenation 
of oils. Contrary to the general impression, it is not necessary to 
agitate the oil and the catalyst very violently with the hydrogen; the 
agitation should especially have the effect of replacing hydrogenated 
portions of the oil in contact with the catalyst by portions not yet 
acted on. 

The various forms of apparatus may be divided into four distinct 
types: 

958. First Type. The oil and hydrogen are simultaneously pro- 
jected on to a catalytic surface. 

This is the principle of the apparatus of Erdmann which is com- 
posed of a vertical nickel cylinder in the centre of which a vertical 
concentric terra cotta cylinder covered with a layer of catalyst with a 
nickel base, turns slowly; the apparatus is heated to 180^ and the oil 
driven by compressed hydrogen is projected onto the surface of the 
cylinder and runs down after it is acted upon.'' 

959. In the apparatus of Schwoerer designed to hydrogenate oleic 
add, the acid carried along by steam superheated to 250-70° and 
mixed with hydrogen is projected on to a helicoidal surface covered 
with nickeled asbestos.'^ 

960. The apparatus of Schlinck belongs in this class; it is com- 
posed of a centrifuge which turns on a vertical ^xis in a closed cylinder 
at the top of which oil and compressed hydrogen are introduced to- 
gether. The basket of the centrifuge is furnished with asbestos im- 
pregnated with catalyst (specially palladium). The oil on account of 
the rapid rotation, the hydrogen on account of its pressure traverse 

** The volume of hydrogen required to saturate any oil is readily calctilated 
from its iodine number. Thus 1 K of oil whose iodine number is 1, requires 
882.0 cc, or 1000 K requires 0.8820 cu.m., of hydrogen measured at 0"* C. and 
760 mm. Hence multiply these figures by the iodine number of the oil in ques- 
tion. 1 K cottonseed oil with iodine number 110 would take 97.02 1. to saturate 
it completely or 35.28 1. of hydrogen to bring it down to an iodine number of 70. 

" Ebdmamn, German patent, 211,669 (1907), C. A., 3, 2732. 
*« ScHWOBBBB, German patent, 199,909 (1906). 



347 HYDROGEN OP LIQUID FATS 

this layer simultaneously and partially combine. The partially hydro- 
genated oil runs out at the bottom; the partially expanded hydrogen 
passes out at the side of the top of the cylinder and is recompressed to 
be sent into another cylinder along with the partially treated oil. 
After passing through a sufficient number of cylinders exactly alike 
the oil is completely hydrogenated.'* 

961. Second Tj^. The oil mixed with the catalyst is atomized 
in an atmosphere of hydrogen which is kept at a suitable tempera- 
ture by steam heat. 

The apparatus of Wilbuschewitch which seems to have given good 
results belongs here. It is composed of an autoclave in the {oim of an 
elongated vertical cylinder the lower end of which terminates in a 60^ 
cone which is kept at 160^. The oil to which the pulverulent catalyst 
has previously been added and which is kept mixed by a suitable 
rotating apparatus, is atomized at the top of the cylinder where the 
falling droplets encounter an ascending current of hydrogen. This 
enters at the lower tip of the cone through a circular chamber the top 
of which is perforated with holes, passes through the oil which has 
acctunlated in the cone, then up the cylinder where it encounters the 
droplets of oil with the catalyst and passes out at the top of the cylin- 
der to be used again. The partially hydrogenated oil which accumu- 
lates in the cone is sent with the catalyst which it carries into a second 
autoclave like the first where the hydrogenation is carried further and 
so on into other cylinders till the desired hydrogenation is obtained.'* 

962. Third Type. The hydrogen is atomized into oil holding the 
catalyst in suspension and heated to a known temperature. 

This is the principle of one form of apparatus of Ellis, which con- 
sists of a conical heating vessel with vertical axis having its apex at 
the bottom and heated by circulation of high pressure steam in a 
double jacket. It is filled with oil for two thirds of its height. The 
catalyst is added through a hole in the top and the hydrogen admitted 
at the desired pressure is circulated by means of a pump, being drawn 
from the top and forced in at the bottom of the cone rising through 
the oil which it agitates and which it hydrogenates thanks to the cata- 
lyst which is suspended in it. The passage of the gas is continued 
till the desired degree of hydrogenation is attained. At this moment a 
horizontal circular filtering disc which is operated by a rod which oc- 
cupies the axis of the cone, is lowered till it rests on the walls of the 
cone near the apex. The oil is filtered through this disc leaving the 

•• ScmjNCK, Oerman pcUerUy 252,320 (1911), C. A., 7, 910 (191Z). — Engliah 
patent, 8,147 of 1911, C. A., 6, 2858 (1912). 

*• Wn^nscHSwrrcH, French patent, 426,343 (1910), /. 8. C. /., 30, 966 (1911). 
— EngHth patent, 30,014 of 1910, /. S. C. /., 31, 443 (1912). 



96S CATALYSIS IN ORGANIC CHEMISTRY 348 

catalyst. The apparatus can be charged with a fresh portion of oil 
which takes up the same catalyst." 

963. Fourtti Type. A vigorous agitation brings the oil, catalyst 
and hydrogen together in the same vessel. 

Kayser's apparatus consists of an autoclave heated to 150-60^ and 
fiUed one fourth full of oil mixed with a pulverulent nickel catalyst 
under hydrogen introduced at the desired pressure. An agitator con- 
sisting of six vanes of metal doth mounted on a metal frame perpen- 
dicular to a horizontal axis, can revolve rapidly and thus cause an 
intimate mixture of gas, oil and solid catalyst.'' 

964. The apparatus of Kimura is very similar.'* In the apparatus 
of Woltmann the agitator rotates on a horisontal axis and carries 
perforated arms through which the hydrogen is sent in under pressure 
corresponding to the rate of its fixation by the oil.^* 

965. Results. The hydrogenation of oil is carried on in quite a 
large number of plants, more than 24 in 1916. 

It enables us to obtain from oils of very inferior quality, such as 
whale oil, fatty materials with odors that are not disagreeable, pos- 
sessing a remarkable consistence along with high melting points. A 
regulated hydrogenation enables us to prepare at will products inter- 
mediate between the oils and the solid fats. 

The fixation of 1 % by weight of hydrogen is sufficient to transform 
coUonseed oil and other oils of that class into substances with the 
consistency of lard. This result may be attained directly by means of 
hydrogenation of the whole mass of the oil and stopped at the desired 
hardness, the operation being carried on at as low a temperature as 
possible so as not to alter the qualities of the oil. But the desired end 
can be more surely attained by hydrogenating a portion of the oil to 
the limit and then mixing this with untreated oil to obtain the de- 
sired hardness. 

966. The table below gives the melting points of the fats obtained 
by complete hydrogenation of the oils or fats.^^ 

•' Ellis, /. Soc Chm. Ind., az, 1155 (1912). 

•• Katbbr, U. S. patenU, 1,004,035 and 1,008,474 (1911), /. S. C. /., 30, 1266 
and 1461 (1911). 

•• EiinTRA, French patent, 486,621 (1918). 

«• WoLTMAN, Englxih patent, 112,293 (1916), C. A., za, 1006 (1918). 

^ Mannich and TmxiA, Mat, {/raun, 2917) 4676. 



349 HYDROGEN OF LIQUID PATS d6d 

Melting points 

Hydrogenated oil Original 

OUveoU 70* 6* 

Almond oil IV -10** 

Peanut oil Gi.S** - 3 

Sesame oU 63.5* -6* 

Poppy seed oQ 70.5* -18* 

Linseed oil 68* -16* 

CodUver oQ 68* -10* 

Cocoa butter 64* 23* 

Tallow 62* 35* 

Lard oil 64* 28* 

The iodine number becomes very small in every case. 

967. The commercial grades do not correspond to such complete 
hydrogenation. They exhale a peculiar, very persistent aromatic odor 
which resists saponification and distillation under reduced pressure. 

Such hardened oils are known tmder the French trade names of 
duratol, talgol, candelite and synthetic taUow. 

Below are given some of the characteristics of such products, 
melting point, iodine number and melting point of the fatty adds : ^ ^ 

M.p. I. No. M.p. of Acids. 

Talgol 35-37** 86.1 38.5* 

Talgol extra 42-44* 63.9 45.5* 

CandeUte 48-«)* 10.4 48.5* 

CandeUte extra 51-62* 10.5 51.8* 

968. Castor oil which does not solidify till below -18*, gives on 
careful hydrogenation a very white hard solid which melts above 80* 
and which is advantageously employed as an electric insulator. 

969. The question of the use of deodorised and hardened oils as 
fats in food has not been completely settled as yet, because we are not 
altogether certain about the toxicity of the small amounts of nickel 
which remain in the materials, amounts that are hardly more than 
0.000002 % if the oils treated were entirely neutral. 

« GlBTH, Seif. ZeU., 39« 1277 (1912). 

« According to infonnatioii obtained from Da. Wbsson, hydrogenation ia carried 
on in the United States by about SO oonoems and hydrogenated oils are impor- 
tant constituents in some 92 brands of shortening. Formerly these were regarded 
as lard substitutes but they have made an independent position for themselves as 
"vegetable shortening" and have found favor with many who object to lard. 

For edible products cottonseed oil is the chief oil that is hydrogenated. The 
aim is to prepare a product that will not be too hard in winter or too soft in summer. 
Sometimes the whole of the oil is hydrogenated. The chief products thus made 



CATALYSIS IN ORGANIC CHEMISTRY 350 

for the American market are Criaco, Sdex, MFB, and Fairoo. These mdt at 33 
to 37* and have iodine numbers running from 76 to 86. By varying the mode of hy- 
drogenationi products with nearly the same melting points but with iodine numbors 
varying as much as 10 points may be obtained. 

By hydrogenating down to an iodine number of 10 to 20 and mixing this very 
hard fat with untreated cottonseed oil the desired consistency may be obtained with 
a much higher average iodine number. This is the most common practice as much 
less hydrogen is required and the fraction of the oil that has to be hydiogenated is 
smalL 

The melting points and iodine numbers of some leading brands are as follows: 

Melting Point Iodine Number 

Scoco 44.4 89.2 

Snowdrift 44.1 89.3 

Armstrong White Cloud 45.8 99.4 

Armstrong Bob White 39.2 93.5 

Fairbanks Boar's head 41.8 100 

Morris Purity 42.0 97.6 

P. and G. Flake white 42.8 90.6 

P. and G. White flake 47.8 87.4 

Swift Jewel 45.6 97.0 

Wilson Advance 44.2 96.9 

Kream Krisp 45.5 97.0 

Highly hydrogenated cottonseed oil is a hard, white, brittle solid and does not 
become rancid. These properties make it a suitable constituent for prepared cake 
flours. 

Vast amounts of fish oils are hydrogenated to be used in making soaps. 

£. £j. R. 



AUTHOR INDEX 



(References are to Paragraphs: a number followed by n" designates a note.) 



Abakumobskaya, Miss L. N., with 

Nametkin, 478 
AboulenCy Jean, with Senderens, 598, 

758, 769, 760 
Acree, S. F., and Johnson, J. M., 202 
Adam, Paul, 241, 896 
Adams, Roger; Kamm, O., and Marvel, 

C. 8., 306, 696, 713 
Adkins, Homer, 797n, 861n 
Ador, E., with Rilh'et, 291 
Adrianowsky, 297 
Akunoff, J., with Lunge, 445 
Alexyef, 899 

Alien, William, and K6lliker, Alfred, 890 
Almedingen, 212 
Aloy, J., and Brustier, 385, 661 
Altmayer with Mayer, 411 
Amberger, C, with Paal, 69, 70, 545 
Ambrey, A., with Bourquelot, 18 
Amouroux, G., 385, 435 
Amouroux, G., with Mailhe, 739 
Amouroux, G., with Murat, 414, 415 
Andrews, C. E., with Boehner, 811 
Ansohatz, Richard, 885, 889, 897 
Anschtltz, R., and ImmendorfF, H., 888 
Antropoff, A. yon, 180a 
Antropoff, A. yon, with Bredig, 180a 
Arbusof, A. E., and Friauf, A. P., 633 
Arbusof, A. E., and Ehrutskii, N. E., 633 
Arbusof, A. E., and Tichwinsky, W. M., 

611, 633, 635 
Armstrong, H. E., and Tilden, W. A., 198 
Aronheim, B., 286 
Arrhenius, Syante, 178, 319, 324 
Asahina, If., 571 
Aschan, Osdan, 929 
Atkinson, R. H., Heyoook, C. T., and 

Pope, W. J., 282n 
Auger, Victor, 893 
Auger, v., and Behal, A., 280 
Austerweil, Gesa, 260n 



Baborovsky, G., and Eusma, B., 276 
Badische, A. S. Fb., 180«, 215, 270, 273, 

511, 730, 876 
Baekeland, Leo H., 792 
Baeyer, Adolf, 90, 893 
Baeyer, Adolf, and Drewsen, Viggo, 798 
Baker, H. B., 73 

Baly, E. C. C, and Krulla, Rudolf, 180 
Bancroft, W. D., 116n, 180a, 180^, 180« 
Barbaglia, G. A., 224 
Barbier, Ph., and Locquin, R., 565 
Bardt, A. Y., with Doroshevskii, 268, 

275 
Barendrecht, H. P., 18Q; 
Bartels, A., with Jannasch, 817 
Bartels, G., with Meigen, 598 
Bauer, A., 211 

Bauer, Maurice, with Brochet, 601 
Baumann, E., 150, 233 
Bayer, A. G., 232 
Bayer and Ck)., 104, 298 
Bayley, 180a 

Becker, C, with Semmler, 570 
Beckmann, E., 185, 189 
Bedford, Fred, 939 

Bedford, F., and Erdmann, E., 598, 943 
Bedford, F., and Williams, C. E., 939, 

941, 943 
B^hal, A., 192, 308 
B^hal, A., with Auger, 280 
Behn, Richard, 892 
Beilstein, F., and Geitner, P., 278 
Beilstein, F., and Euhlberg, A., 287 
Belloni, E., with Carrasoo, 250 
Bergen, J. yon, with Skita, 554 
Bergius, Friedrich, 954 
Bergreen, Henry, 894 
Berl, E., 180r 
Berliner, 180o 
Bemthsen, August, 296 
Berthelot, Maroellin, 21, 60, 84, 148, 165, 



351 



352 



AUTHOR INDEX 



160, I90g, 306, 325, 340, 409, 477, 616, 
637, 660, 749, 750n, 761, 752, 757, 758, 
767, 768, 770, 822, 905, 909, 914, 926 

Berthelot and JungfleiBch, 650, 749 

Berthdot and St. GiUes, 758n 

Bertrand, Gab., 153, 264 

BerieliuB, J., 4, 129 

Bevan, E. J., with CroeB, 268 

DialODllMKl, M., VUU 

Biehler, F., with Paal, 70 

Blackadder, Thomas, 822 

Blaiae,304 

Blanok, F. C, with Tingle, 269n 

Blanes, J. S., with Madinaveitia, 569, 

577 
Blanksma, J. J., with van Ekenstein, 186 
Bodenstein, Max, 8 
Bodenstein, Max, and Fink, Colin G., 

180r 
BodlAnder, G., Koppen, K., 180r 
Bodroux, F., 751, 752, 757 
Bodroux, F., and Tabouiy, F., 420 
Boedtker, Eyrind, 819 
Boedtker, Eyrind, and Halse, O. M., 888 
Boehner, R. S., and Andrews, C. E., 811 
Boehner, R. S., and Ward, A. L., 811 
Bdeseken, J., 81, 87, 224, 643 
Bdeseken, J., and Schinunel, A., 224 
B6e8eken,^J., van der Scheer, J., and de 

Vogt, J. G., 879 
Bdeseken, J., and van Senden, G. H., 664 
Bdeseken, J., van de Weide, O. B., and 

Mom, C. P., 117, 546 
Boeasneck, P., 89 
Boettger, B., 62, 165 
Bone, W. A., and Jerdan, D. S., 409 
Bomwater, J. T., and Holleman, A. F., 

284 
Borodin, A., 795 

Borsche, W., and Heimbtkrger, G., 546 
Borsche, W., and Wollemann, J., 546 
BMer, M., 220 

Bdten, O., with WoUfenstein, 269 
Bouchardat, G., 212 
Boudet, F., 184 
Boudouard, O., 615 
Bougault, J., 203 
BouUay, J. F. G., 691 
Bourquelot, Em., and Aubry, A., 18 
Bouveault, L., 654, 656, 663, 717 
Bouveatdt, L., and Looquin, Ren6, 663 



Boyd, Robert, with Henderson, 459 
Braim, J. von, and Deutsch, H., 897 
Braune, H., 12 
Bredig, G., 68 

Bredig, G., and V. Antropff, 180a 
Bredig, G., and Brown, John Wesley, 272 
Bredig, G., and Carter, S. R., 674 
lig, G., and Fraenkel, W., 12 
lig, G., and Ikeda, K, 116 
Bredig, G., and Joyner, R. A., 836 
Breteau, Pierre, 484, 536, 662, 671, 579 
Breuer, Aug., and Zincke, Th., 220 
Brochet, Andr6, 30, 696, 598, 599, 600, 

603 
Brochet, Andr6, and Bauer, Maurioe, 601 
Brochet, Andr6, and Cabaret, Andr6» 

601,602 
Bromberg, O., with Fischer, 187 
Brooks, Benj. T., and Humphrey, Irwin, 

210,306 
Brown, J. W., with Bredig, 272 
Brown, O. W., and Carridk, L. L., 512 
Bnioe, James, with WiUst&tter, 293, 473 
Brunei, L., 126, 349, 443, 459, 464 
Bruner, L., 291 
Brunner, W., with Skita, 561 
Brustier, V., with Aloy, 385 
Bugarssky, Stefan, 178 
Bum, Friedrich, with Kohn, 293 
Bunsen, R., 180r 
Burrows, George J., 324 
Burstert, H., with Claus, 285 
Buntyn, Walther, 234 
Butlerow, A., 210, 306 

Cabaret, Andr6, with Brochet, 601, 602 

Caldwell, G. C, and Grfiasnuum, A., 184 

Calm, A., 89 

Calvert, F. C, 48, 1806 

Cannissaro, S., 880 

Carpenter, C. C, 372 

Carrasco, O., and Belloni, E., 250 

Cairasoo, O., and Padoa, M., 497, 684 

Carrick, L. L., with Brown, 512 

Carter, S. R., with Bredig, 574 

Carughia, A., with Padoa, 489 

Cathcart, W. R., Jr., and Meyer, Victor, 

893 
Chauvin, A. C, 268 
Chelintaev, V. V., and Trunov, B. V., 

805 



AUTHOR INDEX 



353 



Ch. Fab. auf Aotien (E. Schering), 215 
Chem. Fabr. Buckau, 881 
Chiaves, C.» with Padoa, 490 
Chichibabin, A. £., 310, 686, 807, 810 
Chichibabin, A. K, and Ryumshin, 

P. F.. 901 
Chowdhuri, T. C, with Neogi, 382 
Ciamioian, G., 647 
Ciamioian, G., and Silber, P., 150 
Qaisen, L., 783, 799, 804 
Claisen, L., and ClaparMe, A., 798 
Claisen, L., and Crismer, L., 106 
Claiaen, L., and Ponder, A. C, 798 
Clapardde, with Claisen, L., 798 
Clark, Latham, and Jones, W. N., 414 
Claus, Ad., 207, 893 
Clans, Ad., and Buistert, H., 285 
Clement and Desormes, 324 
Cohen, Ernest, 8 
Cohen, J. B., and Dakin, Henry, D., 

293 
Cohen, Lillian, with Harding, 298 
Colin, H., and Sto6ohal, A., 11 
Colson, Albert, 858 
Commercial Research Co., 269fi 
Consortium/. Electroch. Lid., 228 
Cooke, Stei^en, 166 
Copisarow, Maurice, 893 
Corenwinder, B., 15, 342 
Comubert, R., 602 
Couroy, James T., 161, 837 
Crafts, J. M., 82 
Crafts, J. M., with Friedel, 87, 173, 263, 

295, 297, 883, 889, 890, 893 
Crismer, L., with Claisen, 106 
Cross, C, F., Bevan, E. J., and Heiberg, 

Th., 268 
Crossfield, J., and Sons, and Market, 

K. E., 941 
Curtius, Th., and Foersterling, H. A., 

196 
Curtius, Th., and Lang, J., 332 
Cusmano, Guido, 564, 571 

Dakin, H. D., with Cohen, 293 

Damoiseau, O., 48, 1806, 282 

Daniels, E. A., with Frankforter, 230, 

806 
Darsens, Georges, 30, 56, 243, 360, 389, 

417, 420, 476, 488 MWMaN 

Darsens, G., and Rest, H., 390, 459, 476 



Davy, E., 4 

Davy, Sir Humphrey, 4 

Day, D. T., 946 

Deacon, H., 103, 180r 

Debray, H., with St. Claire-Deville, 64, 

822 
Debus, Heinrich, 180(2, 18(y, 342, 528 
Delepine, Marod, 795 
Delisle, Alfred, 183 
Demole, E., 890 
Demtschenko, S., 224 
Demuth, R., and Dittrich, M., 893 
Denigte, Georges, 268 
Dennstedt, M., 742 
Dennstedt, M., and Hassler, F., 257 
Desormes, with Clement, 324 
Deutsch, H., with v. Braun, 897 
Deuss, J. J. B., 629 
Deussen, Ernst, 560 
Deville, St. Qair, 346 
Dewar, James, 132, 136, 165 
Dey, M. L., with RAy, 815n 
Dimroth, Otto, and W. von Schmaedd, 

816 
Dittrich, M., with Demuth, 893 
Dits, Hugo, 272 
Dixon, Harold B., 73 
Doebereiner, J. W., 62 
Doroshevskii, A. G., and Bardt, A. Y., 

268,275 
Douris, Roger, 208, 419 
Dovgelevich, N., with Ipatief, 920 
Downes, Helen R., with Reimer, 340» 
Downs, C. R., with Weiss, 260r» 
Drachussow, with Ipatief, 594 
Drewsen, Viggo, with Baeyer, 798 
Dreyfus, Henri, 255, 261, 309 
Douris. Roger, 487 
Dubois, H., with MOller, A., 285 
Dubrumfaut, 188 
Duoellies, F., Gay, L., and Raynaud, A., 

292 
Duclaux, Jacques, 139 
Dulk, L., with Meyer, 224 
Dulong, and Th^nard, 637 
Dumas, J., and Pdligot, E., 691 
Dupont, Georges, 195, 565, 577 

Earle, R. B., and Kyriakides, L. P., to 

Hood Rubber Co., 802 
Earie, R. B., with Kyriakides, 723 



354 



AUTHOR INDEX 



Eaaterfield, T. H., and Taylor, Miss 

Clara, M., 843 
Egloff, GustaVi and Moore, Robert J., 

909 
Egloff, Gustav, and Twomey, T. J., 908 
Egloff, Gustav, with Zanetti, 907 
Eijkman, J. F., 392, 452, 454, 474 
Ekl, Elizabeth, with Klemenc, 269n 
Elbe, Karl, 605 
Ellis, Carleton, 941, 962 
Ellis, C, and Rabinovitz, Louis, 601 
Ellis, C, and Wells, A. A., 949 
Engel, R., and de Girard, 780 
Engelder, C. J., 108^, 694, 708, 710 
Engler, C, 150 
Engler, C., and Wild, W., 160 
Engler,.C., and Wdhler, Lothar, 137, 154 
Enklaar, C. J., 415, 416 
Erdmann, E. O., 188, 598, 754, 941, 958 
Erdmann, E., with Bedford, 598, 943 
Erdmann, E., and Rack, E., 944 
Erlenmeyer, Emil, 321, 696 
Erlenmeyer, E. Jr., 203 
Espil, L^, with Sabatier, 12, 16, 56, 80, 

113, 114, 125, 338, 346, 358, 492, 598 
Euler, A., with Euler, H., 225 
Euler, Hans, 324 
Euler, H., and Euler, A., 225 
Evans, E. V., 372 
Evans, P. N., and Sutton, Lena M., 691 

Fabinyi, R., 90 

Fabris, Ugo, with Padoa, 484, 491, 642, 

643 
Fahlberg, List and Co., 285 
Faillebin, with Vavon, 565 
Fajans, Kasimir, 836 
Faraday, Michael, 180o 
Farbw. Meister, Lucius, and BrUning, 

378 
Farbf., v. F. Bayer and Co., 816 
Fassek, W., 795 

Farre, P. A., and Silbermann, J. T., 131 
Fawoisky, Al., 192 
Fenton, H. J. H., 268 
Fenton, H. J. H., and Jackson, Henry, 

268 
Fenton, H. J. H., and Jones, H. O., 268 
Filippov, O. G., 577 
Filippov, O. G., with Ipatief, 589, 590 
Fink, C. G., with Bodenstine, 180r 



Fischer, Emil, 81, 187, 220, 754, 756, 758 
Fischer, E., and Bromberg, O., 187 
Fischer, Emil, and Fischer, O., 890 
Fischer, E., and Giebe, Georg, 782 
Fischer, E., and von Mechel, Lucas, 

793 
Fischer, E., and Morell, R. S., 187 
Fischer, E., and Passmore, F., 221 
Fischer, E., and PUoty, O., 187 
Fischer, E., and Speier, Arthur, 753 
Fischer, E., and Tafel, J., 237 
Fischer, Ernst, with Schmidt, 571 
Fischer, Franz, 931 

Fischer, Franz, and Niggemann, Her- 
mann 930 
Fischer, O., with Fischer, £., 890 
Fischer, O., and K5mer, G., 89 
Fittig, Rudolph, 11, 183, 203, 293, 797 
Fittig, R., and K5hl, Wilhelm, 183 
Fittig, R., and Langworthy, C, F., 183 
Fleitmann, Th., 270 
Foesterling, H. A., with Curtius, 196 
Fokin, S., 12, 252, 254, 266, 526, 556, 

562, 587 
Formin, W., with Tchougaeflf, 570 
Fossek, W., 224 
Foumier, H., 567 
Fownes, G., 194 
Fraenkel, W., with Bredig, 12 
Franchimont, A. P. N., 761 
Franke, Adolf, 226 

Franke, Adolf, and Kohn, Leopold, 234 
Franke, Adolf, and Kohn, Moritz, 227 
Franke, Adolf, and Wozelka, Hermann, 

223 
Frankforter, G. B., and Daniels, £. A«, 

239,806 
Frankforter, G. B., and Kokatnur, V. R., 

806 
Frankforter, G. B., and Kritchevsky, 

W., 806 
Frankland, E., and Kolbe, H., 232 
Frees, Raymond, and Reid, E. Emmet, 

758n 
Fr^bault, A., 428 
Frerichs, G., 598 

Freund, Michael, with Sleinkopf, 931 
Friauf, A. P., with Arbuzof, 633 
Friedel, C, and Crafts, J. M., 87, 173, 

263, 295, 297, 883, 889, 890, 893 
Friedmann, T. E., with Huston, 728 



AUTHOR INDEX 



355 



Gabrieli S., and Neumann, A., 107 

Gambier» with Trillat, 781 

Gangloffy W. C, and Henderson, W. E., 

899 
Garrand, S. F., with Weismann, d54n 
Gfirth, Johann, 967 
Gattennann, Ludwig, 606, 610, 895 
Gattermann, L., with Stockhausen, 886 
Gattermann, L., and Koch, J. A., 298 
Gaudion, Georges, 382, 429, 513, 741 
Gaudion, Geor^^es, with Sabatier, 631, 

634, 641, 643, 644, 645, 680, 681, 

726,923 
Gay, L., with Ducelliez, 292 
Geigy, R., and Eoenigs, W., 893 
Geihnann, W., with Mannich, 656 
Geitner, P., with Beilstein, 278 
Genieser, Ad., with Wilgerodt, 238 
Genveresse, P., 890 
Genun, J., 576 

Gerum, J., with Paal, 72, 546, 556 
Geuther, A., 387, 780 
Gibbs, H. D., 244n, 249n, 254n, 257n, 

260n, 262n, 273n 
Gibello, with Seyewetz, 221 
Giebe, Georg, with Fischer, 782 
Girard, de, with Engel, 780 
Gladstone, J. H., and Tribe, Alfred, 165, 

166, 169, 785 
Glinka, N., with Zelinski, 648, 822 
Godchot, Marcel, 29, 363, 390, 392, 

453,482,483 
Godchot, Marcel, and Taboury, F61ix, 

390, 421, 436, 856 
Godon, F. de, with Mailhe, 530, 682, 

740, 772n, 808, 814 
Godon, F. de, with Babatier, 801 
Goldberg, Irma, 901 
Goldschmidt, Heinrich, and Laisen, 

Halfdan, 283, 288 
Goldsmith, J. N., 661 
G6esmann, A., with Caldwell, 184 
Gottheb, J., 183 

Gottlob, Kurt, with Harries, 235 
Graebe, C., 272 

Graebe, C, and Guye, Ph., 107 
Graebe, C., Liebermann, C., 328 
Graham, Thomas, 65, 536 
Grassi, G., 496 

Greene, W. H., with LeBd, 691 
Griesheim Elektron, with Johnson, 260 



Grignard, Victor, 11, 104 

Grigoreff, 702 

GriUet, 339 

Grimaux, fidouard, 246, 680 

Gross, K. F. L., 215 

Grube, G., and KrQger, J., 233 

Grucarevic, S., and Men, V., 899 

GrOn, A., with G. Schicht, Akt.-Ges., 

846 
GustaTBon, G., 174, 199, 290, 293 
Guthrie, F., 691 
Guttmum, O., with Stock, 8 
Guye; Pd., with Graebe, 107 
Guyot, A., with Haller, 893 

Haag, J., 233 

Haarmann, Wilh., with Tiemann, 329 

Hall, W. A., 933 

Haller, A., 334, 341 

Haller, A., and Guyot, A., 893 

Haller, A., and Lassieur, A., 435 

Haller, A., and Martine, C., 416, 421, 

436, 476, 478 
Haller and Youssouffian, 341 
Halse, O. M., 569 
Halse, O. M., with Boedtker, 888 
Hamonet, J., 902 
Hantzsch, A., 893 
Harbeck, £., and Lunge, G., 180o 
Harding, E. P., and Cohen, Lillian, 

298 
Hamed, Herbert, S., 180g 
Harries, C, 213 

Harries, C, and Gottlob, Kurt, 235 
Hartmann, Wilhelm, with Paal, 180o 
Hartwich, Frank, with Wolffenstein, 893 
Hassler, F., with Dennstedt, 257 
Hatt, Daniel, with Willst&tter, 569, 571 
Hauser, O., and Klotz, A., 778 
Haussknecht, Otto, 184 
Hautefeuille, P., 15 
Heckel, W., with Knoevenagel, 650, 669, 

692, 720 
Heidelberger, M., with Willst&tter, 571 
Heilberg, Th., with Cross, 268 
Heimbtkrger, G., with Borsche, 546 
Heinemann, A«, 815 

Helfrich, O. B., and Reid, E. E., 278n 
Heller, Gustav, and SchOlke, Kurt, 889ft, 

898 
Hemptinne, A. de, 180o 



356 



AUTHOR INDEX 



HenderBon, G. G., and Boyd, Robert, 

450 
HendeTBon, G. G., and Sutherland, 

Maggie M., 403 
Henderson, W. E., with Gangloff, 890 
Henrard, J. Th., 418 
Henii, Victor, I8Q7, 180r 
Henry, L., 236 
Henaeling, 410 

Henenstein, Anna, with Zelinaki, 649 
Hess, K., and liebbrandt, F., 661 
Heycock, C. T., with Pope, 282fi 
Hibbert, Harold, 600 
Higgins, E. B., 044 
Higgins, E. B., with Winuner, 044 
Hobohm, E., with Vorl&nder, 700 
Hoffmann, F., and La Roche and Co., 555 
Hofmann, A. W., 63, 232, 287 
Hofmann, E. A., 262 
Hofmann, E. A., and Schibeted, Helge, 

824 
Hofmann, E. A, and Schumpelt, E., 271 
Hohenegger, C, with Paal, 212, 548 
Holdermann, E., 260n 
HoUenuin, A. F., with Bomwater, 294 
Holtzwart, Rudolf, 231 
Hood Rubber Co., with Earle, 802 
Hoppe, Eduard, 705 
Hoppe^Seyler, F., 150 
Houben, J., and Pfau, A., 560 
Httbl, Baron, 038 
HUbner, H., and Majest, W., 278 
HOfner, G., 180d 
Hugerahoff, A., 630 
Humphrey, Irwin, 210, 306 
Husemann, Aug., and Marm^, Wilh., 330 
Huston, R. C, and Friedmann, T. E., 

728 
Hutin, Albert, 702 

Ikeda, E., with Bredig, 116 
Ujinsky, M., 816 

Immendorff, H., with Anschtltz, 888 
Imray, O., from Fbw. Meister, Lucius 

and BrOning, 228 
Ingle, Harry, with Mackey, 266 
Ipatief, Vladimir N., 78, ISOg, 180r, 
100, 211, 232, 542, 543, 584, 585, 586, 
587, 588, 580, 500, 501, 502, 503, 504, 
505, 508, 667, 670, 604, 702, 706, 711, 
714, 717, 722, 724, 043 



Ipatief and Dovgelevich, N., 020 

Ipatief and Drachussow, 504 

Ipatief, v., Jakowlew, W., and Rakitin, 

W., 502 
Ipatief and Leontowitch, W., 200 
Ipatief and Louvogoi, 580 
Ipatief, v., and Matow, N., 501, 722 
Ipatief, v., and FiUppoy, O., 580, 500 
Ipatief, v., and Rutala, O., 211, 714 
Ipatief, v., and Sohuknan, G. G., 838 
Ipatidf, v., and Sdntowedcy, W., 713 
Ittner, Martin H., 54n, 041n 

Jackson, Heniy, with Fenton, 268 

Jaoobson, Oscar, 201, 887 

Jaoquet, D., with Willst&tter, 563, 560 

Jahn, Hans, 678 

Jakowlew, W., with Ipatief, 502 

Jannasch, P., and Barteb, A., 817 

Jennings, H. 8., 121n 

Jerdan, D. S., with Bone, 400 

Joannis, J., 267 

Job, Andr6, 153 

Johnson, F. M. G., ISOg 

Johnson, G. W., from Griesheim Elek.^ 

260 
Johnson, J. M., with Acree, 202 
Jonas, E. G., with Senunler, 570 
Jones, H. O., with Fenton, 268 
Jones, W. N., with Clark, 414 
Jorissen, W. P., and Reicher, L. Th., 100 
Joyner, R. A., with Bredig, 836 
Jungfleisch, £mile, 278 
Jungfleasch, with Berthelot, 650, 740 

Eametka, T., with Willstfitter, 107, 472, 

470 
Eamm, O., with Adams, and Marvel, 

306, 606, 713 
Eastle, J. H., and Loevenhart, A. S., 

1808 
Easchirski, M., 200 
Eawalier, A., 328 
Eayser, E. C, 041, 063 
Eeghel, Maurice de, 481n 
Eeiser, E. H., with Remsen, 150 
Eekul^, Aug., 182, 183, 705, 706 
Eekul4, A, and Schrotter, H., 100 
Eekul^, A., and Strecker, Otto, 182 
Eekul6, A., and Zincke, Th., 222 



AUTHOR INDEX 



367 



KelbaaiDflkii S. S., with Ostromuiaslen- 

8kii, 784 
Kelber, C, 508, 599 
Eelber, C, and Schwartx, A., 69, 548 
Kempf, R., 276 

Kenner, James, with Knoevenagel, 297 
Keres, Ck>nrad, 877 
Ehrutzkii, N. £., with Arbiuof, 633 
Eiznura, Kanesuke, 964 
Kipping, F. Stanley, 799 
Kijner, N., 444 

King, A. T., and Mason, F. A., 782 
King, V. L., with Willst&tter, 569, 571 
Egeldahl, 272 
Kirchof , 4 

Kidmer, N., 611, 612 
Klemenc, Alfons, and Ekl, Elizabeth, 

269fi 
Klever, H. W., with Staudinger, 235 
Klots, A, with Hauser, 778 
Kluge, Paul, 278 
Knoevenagel, E., 240, 296, 632, 729, 

790,804 
Knoevenagel, E., and Heckel, W., 650, 

669, 692, 720 
Knoevenagel, E., and Kenner, J., 297 
Koch, Erwin, 278 
Koch, J. A , with Gattennann, 298 
KoeUchen, Karl, 229 
Koenigs, W., with Geigy, 893 
Koemer, G., and Menozzi, A., 312 
K6hl, Wilhehn, with Fittig, 183 
Kohn, Leopold, with Franke, 234 
Kohn, Moritz, 697 
Kohn, Moritz, with Franke, 227 
Kohn, Moritz, and Bum, Friedrich, 293 
Kohn, M., and MtOler, N. L., 293 
Kokatnur, V. R., with Frankforter, 806 
Kolbe, H., with Frankland, 232 
Kolbe, H., and Saytzeff, Michael, 165, 

536 
K6lliker, Alfred, with AUen, 890 
Konaortium f. Mektrochemizche In- 
dustrie, 228 
Kopp, Adolph, with Michael, 219 
Koppen, K., with Bodl&nder, 180r 
K6mer, G., with O. Fischer, 89 
Koehdev, F. F., with Ostromuislenskii, 

214 
K6tz, A., and Schaeffer, 550 
Eouraanof, N. J., 889 



Kr&mer, G., and Spilker, A., 217 
Kramer, R. L., and Reid, K E., 707n, 

708n, 744n 
4015 Catalysis 8-8-10 JM 18 gal 6 
Krassuski, K., 200 
Kraut, K., 329 

Krestinsky, V., and Nikitine, N., 713 
Kritchevsky, W., with Frankforter, 806 
KrOger, A., 278 
KrOger, F., ISQ; 
KrOger, J., with Grube, 233 
KrOger, Paul, with Tiemann, 198, 800 
KruUa, Rudolf, with Baly, 180i 
Kuhlberg, A., with Bielstein, 287 
Kuhhnann, F., 342, 529 
Kutscheroff, M., 309 
Kuzma, B., with Babarovsky, 276 
Kuznetzov, M. I., 623, 920 
Kvapiahevskii, K. V., with Zal'ldnd, 

548,566 
E;yTiakide8, L. P., 726 
Kyriakides, L. P., and Earle, R. B., 723» 

802 

Lafont, J., 216 

TAining- 146 

Landolph, F., 211 

Lang, J., with Curtius, 332 

Langer, C., with Mond, 614 

Langmuir, Irving, 180(2, 180e, 18Qf, 18Qp 

Langworthy, C. F., with Fittig, 183 

Larsen, Half dan, with Goldschmidt^ 283» 

288 
Lassieur, A., 435 
Lassieur, A., with Haller, 435 
Laurent, A, 184 
Lasarew, 293 
Lebaoh, H., 792 
Le Bel and Greene, W. H., 691 
Le Chatelier, 131 
Leeds, Albert R., 150 
Lehmann, F., 583 
Lemonie, Georges, 2, 11, 20, 32, 34, 38, 

49, 63, 77, 679 
Leontowitch, W., with Ipatief, 200 
Leprinoe, and Siveke, 5^ 
Lerczynska, Miss I.» with Piotet, 936 
Leroux, Henri, 481 
Leroy, A. J., 293 

Lesooeur, H., and Rigaut, A, 230 
R«, 566 



358 



AUTHOR INDEX 



Lespieau, R., and Vayon, G., 666 

Lewis, W. C. MoC., ISQ;, 180r 

Lewkowitsch, 314, 318 

Libavius, 4 

lieben, Adolf, 104, 222, 321, 795 

liebennann, C, with Graebe, 328 

liebig, Justus von, 11, 312 

liebig, Justus yon, with Wdbler, 220 

liebrandt, F., with Hess, 561 

Limpricht, H., 278, 320, 851 

lindenbaum, Ernst, with Naumann, 

260,269 
Lineburger, C. E., 890 
lipp, Peter, 478 

lippmann, Edmund O. von, 324 
livache, Ach., 266 
Lobry de Bruyn, C. A., 186 
Locquin, R., with Barbier, 565 
Locquin, Rcai6, with Bouevault, 663 
Loevenhart, A. S., with Kastle, 180s 
Loew, O., 62, 221, 562, 621 
Longman, J., 298 
Lorin, 822 
Louise, E., 797 
Louvogoi, with Ipatief , 589 
Ldwenhers, Richard, 315 
Lucas, O. D., with Valpey, 933 
Ludwig, H., 329 
Lunge, G., and Akunoff, J., 445 
Lunge, G., with Harbeck, 180o 

McAfee, A. M., 935 

Mackey, W. McD., and Ingle, Harry, 
266 

Madinaveitia, A., 117, 580 

Madinaveitia, A., and Blanes, J. S., 569, 
577 

Mahl, with WOhler, 75 

Mailhe, Alphonse, 383, 386, 435, 514, 
735, 745, 833, 842, 843, 849 

Mailhe, Alphonse, with Sabatier, 75, 77, 
78, 112, 127, 162, 169, 170, 258, 337, 
343, 347, 363, 385, 387, 391, 404, 406, 
407, 420, 422, 430, 431, 437, 438, 442, 
457, 458, 461, 470, 475, 486, 495, 521, 
617, 621, 628, 641, 651, 655, 660, 672, 
673, 674, 677, 689, 693, 702, 704, 706, 
708, 709, 714, 715, 717, 731, 733, 734, 
735, 737, 739, 743, 744, 745, 746, 762, 
766, 769, 771, 772, 774, 777, 785, 786, 
787, 788, 789, 791, 794, 822, 823, 824, 



834, 839, 842, 843, 844, 845, 849, 850, 

852, 853, 856, 857, 858, 866, 873, 876, 

878, 916, 923 
Mailhe, A., and Amouroux, 739 
Mailhe, Alph., and de Godon, F., 539, 

682, 740, 772n, 808, 814 
Mailhe, A., and Murat, Maroel, 384, 

385,494 
Majest, W., with Habner, 278 
Mamontoff, W., 691 
Mannich, C, 646 

Mannich, C, and Geilmann, W., 656 
Mannich, C, and Thiele, 966 
Mansfield, Johannes, with SchoU, 685 
Markaiyan, Miss V., with Zal'kind. 

548, 566 
Markel, K. E., with Qroesfield, 941 
Marrn^, Wilh., with Husemann, 330 
Martine, C, with Haller, 416, 421, 436, 

476, 478 
Mason, F. A, with King, 782 
Mason, John E., and Wilson, John, 262 
Masson, A., 691 

Matignon, C, and Trannoy, 75, 259 
Matow, N., with Ipatief, 591, 722 
Matthews, F. E., and Strange, E. H., 

213 
Maxted, Edward B., 10, 180o, 954 
Mayer, E. W., with Willstatter, 565, 569 
Mayer, Max, and Altmayer, 411 
Mechel, Lukas von, with E. Fischer, 

793 
Meigen, W., and Bartels, G., 598 
Meissel, M., 899 
Meissl, E., 325 
Measter, Lucius, and BrOning, Farbw, 

261,299 
Meister, Lucius, and BrCkning, with 

Imray, 228 
Melsens, 48 

Menozsi, A., with Koemer, 312 
Menschutkin, N., 38, 768, 769 
Mereshovski, B. K, 192, 193, 472 
Merz, v., with Grucarevic, 899 
Metsger, R., with Schmidt, 454, 484 
Meyer, Ernst von, 231, 232 
Meyer, Lothar, 294 
Meyer, Richard, and Tansen, August, 

683 
Meyer, Victor, with Cathcart, 893 
Meyer, Victor, and Dulk, L., 224 



AUTHOR INDEX 



359 



Meyer, W. A.» with Skita, 09, 545, 551, 

552, 554, 557, 559, 560 
Michael, Arthur, 104, 239 
Michael, Arthur, and Kopp, Adolph, 

219 
Michael, A., Scharf, E., and Voigt, K., 

200 
Michieb, Louis, 874 
Mignonac, Georges, 380, 512, 809 
Millar, W. S., 12 
Miller, W. I^ash, 180^ 
Milligan, C. H., 538n, 700n, 772n, 778fi 
Millon, £., with Reiset, 637 
Moeser, Ludwig, with Naumann, 260, 

269 
Moissan, Henri, 73, 136, 147 
Moissan, H., and Moureu, Ch., 637, 914 
Mom, C. P., with B5eseken, 117, 546 
Mond, Ludwig, Langer, C, and QuinckOi 

F., 614 
Mond, Ludwig, Ramsay, William, and 

Shields, John, 136, 137 
Moore, H. K., Richter, G. A., and Van 

Arsdel, W. B., 947, 952 
Moore, R. T., with Egloff, 909 
Morrell, R. S., with Fischer, 187 
Mouneyrat, A., 199, 284, 289 
Mouneyrat, A., and Pouret, Ch., 284 
Moureu, Ch., with Moissan, 637 
Mulder, E., 246 

MQller, A, and Dubois, H., 285 
Mtlller, Hugo, 278, 795 
MtOler, N. L., with Kohn, 293 
MtOler, 287 
MOntz, A, 325 
Murat, Marcel, 475 
Murat, Marcel, with MaUhe, 384, 385, 

494 
Murat, Marcel, with Sabatier, 343, 348, 

362, 364, 369, 389, 415, 449, 452, 453, 

455, 471, 475, 488, 523, 538, 714, 720, 

721 
Murat, M., and Amouroux, G., 414, 415 
Mylo, B., with Wohl, 725 

Nametkin, S. S., and Abakumovskaya, 

L. N., 478 
Naumann, Al^., Moser, Ludwig, and 

Lindenbaum, Ernst, 260, 269 
Neuberg, Carl, 268 
Neubexg, C, with Wohl, 237 



Nencki, M., 899 

Neogi, P., and Chowdhuri, T., C, 382 
Neumann, A., with Gabriel, 107 
Neumann, G., 137 
Niederh&usem, Heinrich V., 787 
Niggemann, H., with Fischer, F., 930 
Nikitine, N., with Krestinsky, 713 
Nord, F., with Skita, 555 
Norman, W., 542, 598, 940, 941, 945 
Norman, W., and Pungs, W., 598 
Norman, W., and Schlick, F., 80, 583 
Norton, L. M., and Preeoott, C. O., 691 

(Economides, S., 795 
Oehme, H., with Paal, 555 
Oelsner, K., with Semmler, 570 
Oldenberg, Babette, with Oldenberg, 272 
Oldenberg, Hermann, and Oldenberg, 

Babette, 572 
Olivier, S. C. J., 893 
Orloff, E. I., 253, 254, 256 
Omdorf, W. R., 223 
Ostromuislenskii, I. I., and Kelbasin- 

ski, S. S., 784 
Ostromuislenskii, I. I., 'and Eosheler, 

L I., 214 
Ostwald, W., 8, 37, 140, 178, 180, 336 
Overton, B., 893 

Paal, C, 69, 72, 248, 251, 542, 544, 547, 

555 
Paal, C, with Skita, 555 
Paal, C, and Amberger, C, 69, 70, 545 
Paal, C, Biehler, F., and Steyer, H., 70 
Paal, C, and Gerum, J., 72, 546, 556 
Paal, C, and Hartmann, Wilhelm, 180o, 

546 
Paal, C, and Hohenegger, C«, 212, 548 
Paal, C, and Oehme, H., 555 
Paal, and Schwan, A., 548, 558 
Paar, W., with Wolffenstein, 269n 
Padoa, Mauriiio, 485 
Padoa, M., with Carrasco, 497, 684 
Padoa, M., and Canighi, A., 489 
Padoa, M., and Chiaves, C, 490 
Padoa, M., and Fabris, U., 484, 491, 

642,643 
Padoa, M., and Ponti, 371, 434, 487, 619 
Padoa, M., and Scagliarini, G., 647 
Parcus, E., and ToUens, B., 188 
Pardee, A. M.» and Reid, E. E., 340n 



360 



AUTHOR INDEX 



Parker, H. K., 285n 

Passmorei F., with Fischer, 221 

Patemo, E., 282 

Patrick, W. A., 75n, 180c 

Patry, E., with Pictet, 270 

Pauwels, Joseph, 236 

Peachey, 8. J., 11, 104, 108 

Pdligoti E., with Dumas, G91 

Peridn, W. H., 107 

Perkin, W. H. Jr., 224, 79B 

Perrin, Jean, I8Q7 

Peter, Arnold H., 091 

P6tricou, 288 

Petri, Camille, 182 

P^trie, 75 

Pfau, A, with Houben, 669 

PhiUips, P., 4 

Pictet, Aim^, and Lerczynska, 936 

Pictet, Aim6, and Patry, E., 270 

Piloty, O., with Fischer, 187 

Pinkney, 261n 

Piria, R., 328, 329, 851 

Pishchikov, P. V., with Zal'kind, 38 

Plattner, 75 

PlotnikoY, V. A., 284 

Plummerer, Rudolf, with Wilst&tter, 835 

Ponder, A. C, with Qaisen, 798 

Ponti, with Padoa, 371, 434, 487, 619 

Pope, Wm. J., with Atkinson, 282n 

Potter, H. M., with Roeanoff, 32f 

Presoott, C. O., with Norton, 691 

Priebs, Bemhard, 89, 803 

Pring, John N., 525 

Prins, H. J., 198, 216, 242, 625, 903 

Pungs, W., with Norman, 598 

Purgotti, A., and Zanichelli, L., 563 

Quincke, F., with Mond, 614 

Rabinovits, Louis, with Ellis, 601 
ilack, E., with Erdmann, 944 
Radziewanowski, Cornelius, 886, 888 
Rai, Hashmat, 265 
Rakitin, W., with Ipatief, 592 
Ramsay, Wm., with Mond, 136, 137 
Rather, J. B., and Reid, E. E., 601 
Raupenstrauch, G. A., 795 
R&y, J. N., and Dey, M. L., 815n 
Raynaud, A., with Duoelliez, 292 
Reboul, E., 212 
Reformatski, A., 298 



Regnault, V., 131 

Reich, 75 

Reicher, L. T., 178 

Reicher, L. T., with Jarisaen, 100 

Reid, E. Emmet, lOn, 241n, 285n, 340is 

538fi, 696n, 772n, 816n, 778n, 947n 
Reid, E. Emmet, with Freas, 758n 
Reid, E. Emmet, with Helfrich, 278 
Reid, E. Emmet, with Kramer, 707^, 

708n, 744n 
Reid, E. Emmet, with Pardee, 340fi 
Reid, E. Emmet, with Rather, 601 
Reid, K Emmet, with Van Epps, 812 
Reimer, Marie, and Downes, Helen R., 

340n 
Reiset, J., and Millon, E., 637 
Remsen, Ira, and Reiser, E. H., 150 
Riban,7., 216, 795 
Richardson, A. S., 269n 
Rich6, 397 

Richter, G. A., with Mooie, 947, 952 
Richter, W., with Semmler, 570 
Rideal, E. K., 18Q; 

Rideal, E. K., and Taylor, H. 3., 180s 
Rigaud, L., 328 
Rigaut, A., with Lescoeur, 230 
RiUiet, A., and Ador, E., 291 
Risse, F., with Semmler, 570 
Ritter, H., with Skita, 549, 642 
Rochleder, F., 340 
Roenisch, P., with Semmler, 570 
R6ntgen, W. C, 324 
Roeanoff, M. A., and Potter, H. M., 

324 
Rosenmund, K. W., 575 
Rosenmund, K. W., and Zetsche, F., 545 
RoBsel, Arnold, 220 
Rost, H., with Darzens, 390, 459, 476 
Rothmund, Victor, 324 
Roux, L6on, 199, 293 
Rosanov, N. A., 193, 472 
Russanow, A., 280 
Rutala, O., with Ipatief, 211, 714 
Ryumdiin, P. F., with Chichibabin, 901 

Sabatier, P., 10, 146, 180, 364, 397, 399. 

400, 402, 416, 418, 511, 515, 590, 932, 

939 
Sabatier, P., and Espil, L60, 12, 16, 56, 

80, 113, 114, 125, 338, 346, 358, 492, 

598 



AUTHOR INDEX 



361 



Sabatier, P., and Gaudion, G., 631, 634, 
641, 643, 644, 645, 6g0, 681, 726 

Sabatier, P., and de Godon, F., 801 

Sabatier, P., and Mailhe, Alpbonae, 76 
77, 78, 112, 127, 162, 169, 170, 268, 
337, 343, 347, 368, 3P6, 887, 391, 404 
406, 407, 420, 422, 430, 431, 487, 438 
442, 457, 458, 461, 470, 475, 486, 405 
521, 617, 621, 628, 641, 651, 655, 660, 
672, 673, 674, 677, 689, 693, 702, 704 
706, 708, 709, 714, 716, 717, 781, 733 
734, 735, 737, 739, 743, 744, 745, 746, 
762, 766, 769, 771, 772, 774, 777, 785 
786, 787, 788, 789, 791, 794, 822, 833 
824, 834, 839, 842, 843, 844, 845, 849 
850, 852, 853, 856, 857, 858, 866, 873 
876, 878, 916 

Sabatier, P., Mailhe, Alph., and Gaudkm, 
G., 923 

Sabatier, P., and Murat, M., 348, 348 
362, 364, 369, 389, 415, 449, 452, 453 
455, 471, 475, 488, 523, 538, 714, 720 
721 

Sabatier, P., and Sendeiena, J. B., 26, 
111, 208, 343, 351, 362, 368, 370, 374 
375, 376, 377, b78, 379, 888, 394, 396 
410, 413, 414, 419, 424, 425, 427, 433 
435, 436, 446, 449, 451, 456, 460, 464 
466, 467, 468, 469, 471, 475, 477, 481 
482, 494, 497, 500, 501, 502, 508, 504 
506, 508, 509, 510, 511, 512, 515, 517 
518, 519, 520, 521, 526, 527, 530, 531 
533, 534, 542, 614, 616, 619, 622, 637 
652, 654, 656, 658, 659, 660, 664, 666 
668, 683, 701, 832, 912, 914, 916, 919 
920, 925, 928, 939 

Sainte-Clairfr-Deville, H., 216 

Sainte-Qaire-Deville, H., and Debray, 
H., 64, 822 

Sandmeyer, T., 91, 607, 608, 609 

Sastry, 8. G., 265 

Sayre, R., with Schorger, 235 

Saytieff, Michael, 586, 806 

Saytaeff, Michael, with Kolbe, 165, 536 

Soagliarini, G., with Padoa, 647 

Schaeffer, with K6ts, 550 

Scharf, E., with Michael, 200 

Scheiber, Johannes, 893 

Scheufelen, Adolf, 293 

Sehiapaielli, Ceeaie, 208 

I, Hel0e, with Bolmann» 824 



Schicht, G., Akt.-Ge8., 942 

Schicht, G., Akt.-GeB., and GrOn, A., 846 

Schiel, J., 282 

Schinunel, A., with B6enken, 224 

Schlick, F., with Norman, 80 

Schlinck, H., and Co., 960 

Schmaedel, W. von, with Dimioth, 816 

Schmidt, C., with Schraube, 206 

Schmidt, J., and Fischer, Enut, 571 

Schmidt, J., and Metsger, R., 454, 484 

Schneider, W. von, 210 

SchneDenberg, Albert, with Sonn, 565 

Schoenbein, C. F., 180o 

SohoU, Roland, and Mansfield, Jo^ 

hannes, 685 
SchoU, Roland, and Seer, Christian, 685 
SchoU, R. Seer, Chr., and Wellaenbook, 

R., 685 
Scholtz, M., 799 
Sch6ne, Em., 160 
Schanfeld, H., 944 
Schorger, A. W., 930 
Schorger, A. W., and Sayre, R., 285 
Schraube, C, and Schmidt, C, 206 
Schrohe, A., 212 
Schrotter, H., with Kekul^, 199 
SchOlke, Kurt, with Heller, 889n, 896 
Schulman, G. G., with Ipatief, 838 
Schultse, Paul, 820 
Schumpelt, K., with Hofmann, 271 
Schfltsenbeiger, 637 
Schwarts, A., with Kelber, 69, 548 
Schwars, A., with Paal, 548, 558 
Schwoerer, 941, 969 
Sdzitowecky, W., with Ipatief, 713 
Seelig, E., 283, 285, 286 
Seer, Christian, with SchoU, 685 
Seiichideno, 115 

Seligman, R., and Williams, P., 12 
Semmler, F., W., and Becker, C., 570 
Semmler, F., W., Jonas, K. G., and 

Oelsner, K., 570 
Semmler, F. W., Jonas, K. G., and 

Richter, W., 570 
Semmler, F. W., Jonas, K. G., and 

Roenisch, P., 570 
Semmler, F. W., and Riase, F., 670 
Senden, G. H. von with B6e0eken« 664 
Senderens, J. B., 78, 511, 694, 606, 700^ 

713, 718, 719, 725, 840, 844, 849, 855^ 

858, 878, 874, 878, 881 



362 



AUTHOR INDEX 



Sendereos, J. B., with Saba^ier, 26^ 111, 
208, 343, 351, 362, 368, 370, 374, 375, 
376, 377, 378, 379, 388, 394, 396, 410, 
413, 414, 419, 424, 425, 427, 433, 435, 
436, 446, 449, 451, 456, 460, 464, 466, 
467, 468, 469, 471, 475, 477, 481, 482, 
494, 497, 500, 501, 502, 503, 504, 506, 
508, 509, 510, 511, 512, 515, 517, 518, 
519, 520, 521, 526, 527, 530, 531, 533, 
534, 542, 570, 614, 616, 619, 622, 637, 
652, 654, 656, 658, 659, 660, 664, 666, 
668, 683, 701, 832, 912, 914, 916, 919, 
920, 925, 928, 939 

SendereDs, J. B., and Abouleno, Jean, 
598, 758, 759, 760 

Sdn^chal, A., with Colin, 11 

Seyewetz, A., and Gibello, 221 

Bhaw, T. W. A, 601 

Shxoeter, G., 481n 

Shukow, A. A., 942 

Siemens, 397 

Silber, P., with Ciamician, 150 

Silbermann, J. T., with Favre, 131 

Silva, R. D., 890 

Siveke, with Leprinoe, 542 

Skita, A., 71, 420, 546, 548, 553, 559, 
560 

Skita, A., and Brunner, W., 561 

Skita, A., and Meyer, W. A., 69, 545, 
551, 552, 557, 559, 560 

Skita, A., Meyer, W. A., and Bergen, 
J. von, 554 

Skita, A, and Nord, F., 555 

Skita, A., and Paal, C, 555 

Skita, A., and Bitter, H., 549, 642 

Skraup, H., 182 

Smimof, V. A., 369, 465 

Snethlage, H. C. S., 12 

Soc. de St^arinerie, and Savonnerie de 
Lyon, 949 

Sommelet, Marcel, 818, 889, 899 

Sommer, Rudolf, 268 

Sonn, Adolf, and Schnellenberg, Albert, 
565 

Sonnenfeld, Eugen, with Willstfitter, 251 

Spier, Arthur, with Fischer, 753 

Spilker, A., with Er&mer, 217 

Spohr, J., 324 

Sponagely Paul, with Ulhnann, 904 

Sprent, C, 413, 713 

Squibb, Edward R., 161, 180a, 837 



Staudinger, H., and ElevBr, H. W., 235 
Steinkopf , Wilhelm, and Freund, Michr 

ael,931 
Steyer, H., with Paal, 70 
St. Gilles, Pean de, with Berthelot, 758vi 
Stock, A., and Guttmann, O., 8 
Stockhausen, F., and Gattermann, L., 

886 
Stoll6, R., 201 

Stone, W. E., and Tollens, B., 727 
Strange, E. H., with Matthews, 213 
Strecker, Adolph, 240 
Strieker, Otto, with KekuM, 182 
Strutt, R. J., 180c 
Sukberg, N., with Thiele, 203 
Sutherland, M. J., with Henderson, 463 
Suto, K., 268 
Sutton, Lena M., with Evans, 691 

Taboury, F^x, with Bodroux, 421 
Tabouiy, F61ix, with Godohot, 390, 421, 

436,856 
Tafel, J., with Fischer, 237 
Tanatar, S., 182, 193 
Tanret, C., 188 

Tansen, August, with Meyer, 683 
Taylor, Clara M., with Easterfield, 843 
Taylor, H. S., 1806, 180o, 180g 
Taylor, H. S., with Rideal, 1808 
Tchougae£F, L., and Fomin, W., 570 
Teuchert, R., 312 
Th^nard, with Dulong, 637 
Thiele, with Mannich, 966 
Thiele, Johannes, and Sulzberger, N., 

203 
Tiemann, Ferd., 191 
Tiemann, Ferd., and Haaimann, Wilh., 

329 
Tiemann, F., and KrQger, Paul, 198, 800 
Tikhvinskii, V. M., with Arbusow, 611, 

633,635 
Tilden, W. A., with Armstrong, 198 
Tingle, J. B., and Blanck, F. C, 269n 
Tischenko, V. E., 228, 299 
Tollens, B., with Parens, 188 
Tollens, B., with Stone, 727 
Tollens, B., with Yoder, 727 
Tollens, B., and Wigand, P., 83 
Tomthwaite, 75 

Trannoy, with Matdgnon, 75, 259 
Traube, M., 73 



AUTHOR INDEX 



363 



Trey, H., 317 

Tribe, Alfred, with Gladstone, 105, 166, 

169. 785 
Trillat, A., 73, 249, 253, 256 
Trillat, A., and Gainbier, 781 
Trunov, B. V., with Chelintaev, 805 
Tschelinzeff, W., 301 
Turbaba, D., 22 
Turner, Edward, 10, 116 
Twomey, T. J., with Egloff, 908 
Tyndall, 18Q; 

Uklonflkaja, Miss, N., with ZeUnski, 649 

UUmann, Frits, 901 

UUmann, F., and Sponagel, Paul, 904 

Valpy, O. H., and Lucas, O. D., 933 
Van Arsdel, W. B., with Moore, 947, 952 
Van der Sdieer, J., with BOeseken, 879 
Van der Weide, O. B., with B5eseken, 

117, 546 
Van Ekenstein, W. A., with Lobry de 

Bruyn, 186 
Van Ekenstein, W. A., and Blanksma, 

J. J., 186 
Van Epps, G. D., and Reid, E. Emmett, 

812 
Van't Hoff, 139, 175 
Varet, Raoul, and Vienne, G., 241 
Vavon, G., 63, 567, 568, 570 
Vavon, with Lespieau, 566 
Vavon and Faillebin, 565 
Veley, V. H., 8, 269n 
Veraguth, H., with WiUst&tter, 480 
Verein, Ghininfabr. Zinuner, and Co.| 

572,604 
Verein, f. Ghem. Ind., 254 
Verinigte Ch. Werke, 946 
Vienne, G., with Vaiet, 241 
Vignon, Lto, 269n, 540 
ViUiers, A., 153 

Vogt, J. D. de, with Bdeeeken, 879 
Voigt, with Michael, 200 
Vorl&nder, D., and Hobohm, K, 799 

Wacker, L., 274 

WaldBchmidt-Leits, Ernst, with Will- 

stAtter, 62n, 167n, 562n, 563n, 573n, 

943n, 947n. 
Wallach, O., 198, 205, 546, 552, 797 
Wallach, O., and WOsten, M., 97 



Ward, A. L., with Boehner, 811 
Waser, E., with WiUst&tter, 480, 535, 

571 
Weismann, Charles, and Garrand, 8. F., 

654n 
Weiss, J. M., and Downs, C. R., 260n 
Wells, A. A., with Ellis, 949 
Wellsenbock, R., with Scholl, 685 
Wesson, David, 967n 
Wilbaut, J. P., 683 
Wieland, Heinrich, 251 
Wieland, H., and Wishart, R. S., 579 
Wigand, P., with Tollens, 83 
Wiggers, A., 307 

Wilbuschewitch, M., 941, 945, 961 
Wild, W., with Engler, 150 
Wilde, M. P. von, 342, 526 
Wilfarth, H., 272 
Willgerodt, C, 283 

Willgerodt, C., and Genieser, Ad., 238 
Williams, C. E., with Bedford, 939, 941, 

943 
Williams, P., with Seligman, 12 
Williams, R. R., and Gibbe, H. D., 254n 
Williamson, Alexander, 159, 169, 848, 

851 
WiUst&tter, Richard, 542, 562, 563 
Willst&tter, Richard, and Bruoe, James, 

293,473 
Willst&tter, R., and Hatt, D., 569, 571 
Willst&tter, R., and Heidelberger, M., 

571 
Willst&tter, R., and Jacquet, D., 563, 

569, 571 
Willst&tter, R., and Eametaka, T., 197, 

472,479 
Willst&tter, R., and King, V., 569, 571 
Willst&tter, R., and Mayer, E. W., 565, 

569 
WiUst&tter, R., and Pummerer, Rudolf, 

835 
Willst&tter, R., and Sonnenfeld, Eugen, 

251 
WiUst&tter, R., and Veraguth, H., 480 
WiUst&tter, R., and Waser, E., 480, 535, 

571 
Willst&tter, Richard, and Waldschmidt* 

Leiti, Ernst, 62n, 167n, 562n, 563n, 

573n, 943n, 947n 
Wilsmore, N. T. M., 829 
Wilson, John, with Mason, 262 



3M 



AUTHOR INDEX 



TVImmer, K. H., «nd Higgins, E. B., 044 

Winkler, ClemfiDS, 73 

Wippennazm, R., 230 

Wiachnegnulakyy A., 210 

Wishart, R. 8., with WieUnd, 579 

WitMmann, Edgar, J., 726 

Wohl, A., 324 

Wohl, A., and Mylo, B., 725 

W5hler, F.» and Liebig, Jivtus, 220 

Wdhler, F., and Mahla, 75 

Wfifaler, Lothar, with Engter, 137, 154 

Wohl, A., 94 

Wohl, A., and Neuberg, C, 237 

Woker, MisB Gertrude, 18Q; 

Wolffenatein, R., and Bdters, O., 209 

WolflPenatein, Riohard, and Hartwioh, 

Frank, 893 
Wolffenstein, R., and Paar, W., 269ii 
WoUemann, J., with BorBofae, 540 
WoQraih, A., 278 
Woltman, A., 904 
Woog, Paul, 257, 259 
Woselka, Hermann, with Frank, 228 
WurtB, Adolphe, 11, 219, 307, 334, 006 
WQsten, M., with Wallaoh, 97 

Yoder, P. A., and ToUens, B., 727 
YouasoufSan, with Haller, 341 



Zagumennl, A., 092 

Zalldnd, Y. 8., 548, 500 

Zal'kind, Y. 8., and Kyapbhevskii. 

K. v., 548, 500 
Zal'kind, Y. 8., and Mia Maricaiyaa, 

v., 648, 600 
Zal'kind, Y. 8., and PiahohokoT, P. V^ 

38 
Zanettt, C. U., 742 
Zanetti, J. E., and Egkiff, Q., 907 
ZanieheUi, L., with Purgotti, 503 
Zdrawkowitch, Milan R., 02 
Zei8e,02 
Zelinaki, H., 302 
Zelinaky, N. D., 390, 472, 478, 534, 535, 

049, 900, 934 
Zelinaky, N. D., and Qlinka, N^ 048, 

822 
Zelinaky, N. D., and Hersenatein, Miaa 

Anna, 049 
Zelinaky, N., and Uklonakiga, Mia N., 

049 
Zetaohe, F., with Roaenmund, 545 
Zinckp, Tk, with Bieuer, 220 
Zincke, Th., with Kekul4, 222 
Zinin, N., 203, 220 
Zaigmondy, R., 18Q; 



SUBJECT INDEX 

(Referenoes are to Pangrai^: a number foUowed by "n" designates a note.) 



Absorption of gases, 131, 135 
Acenaphthene, hydrogenated, 482 
Acetaldehyde, 219, 222, 261, 700, 724, 
725 

into aoetals, 780, 782 

from acetylene, 02, 309, 310 

as catalyst, 106, 310, 312 

condensed, 52, 592, 780, 782, 795, 
796, 801, 807 

crotonised, 795, 801 

deoompoeed by Pd., 623, 680 

into ester, 228 

formed, ISOg, 200 

hydrogenated, 432, 439, 494, 538, 
593, 664, 668, 670, 673 

with hydrogen sulphide, 810 

by oxidation, 249, 254, 256, 268 

oxidised, 255, 260, 261 

preparation of, 309 
Aoetal, by oxidation, 249 
Aoetals, 81, 97, 175, 249, 305, 779-783 

formed, 81, 106, 249 

hydrolysis of, 322, 323 

preparation of, 7^ 
Acetamide, dehydrogenated, 811 

hydrolysed, 336, 386 
Aoetanhydride, 107 

decomposed, 829 

in esterification, 761 

into ketone, 857 
Acetanilide in synthesis, 901 
Acetic acid, into acetone, 161, 180a, 
840-845 

from acetylene, 255 

from alcohol, 48, 150, 255, 257, 
261 

as catalyst, 106, 215, 687, 780 

chlorinated, 280 

decomposed, 831, 843 

esterified, 750, 758, 760, 771 

esters of decomposed, 863 



formed, 1806 

into nitrile, 812 

by oxidation, 48, 150, 255, 257, 261 

retarder, 11 
Acetols, 783 
Acetone, into acetol, 783 

with chloroform, 238 

condensed, 238, 783, 797, 797fi, 798, 
800, 801, 805 

condensed with aldehydes, 798 

condensed with bensaldehyde, 798 

condensed with dtral, 800 

condensed with o.nitrobensaldehyde, 
798 

crotonised, 797, 798 

decomposed, 620, 659, 665, 668 

formed, 161, 180a, 249, 809, 831, 837, 
844 

hydrogenated, 435, Co 503, Cu 594, 
Fe 593. Ni 588, 596, Ft 567, Zn 595 

by oxidation, 249, 254a 

preparation of, 161 
Acetone-oxime hydrogenated, 383 
Acetonitrile as catalyst, 108, 606 

formed, 871 

polymerised, 50, 231, 427 
Acetonyl-acetone hydrogenated, 440 
Acetophenone, 848, 849 

catalytic solvent, 38 

condensed, 799 

by Friedel and Crafts reaction, 891, 
893 

hydrogenated, 389, 455, 538, 539, 
568 
Acetophenone-oxime hydrogenated, 384 
Acet-oxime hydrogenated, 383 
Acetyl*acetone hydrogenated, 439, 595 
Acetyl-brom-glucose condensed, 793 
Acetyl chloride formed, 280 

in F. and C. reaction, 891-893 
Acetylation, 81, 240 



865 



366 



SUBJECT INDEX 



Aoetyl-chlorainino-benieiie iaom., 202 
Aoetyl-cydo-hexene hydrogeoated, 476 
Aoetyl-diphenyl-aiiime, Bjm., 901 
Acetylene, 38, 102, 306-^10 

condeDaed, 686, Co 928, Cu 916, Fe 
928, Ni 925-928 

condensed with benxene, 241 

decomposed, 637, 913-920 

fonned,409 

hydrated, 27, 92, 308 

hydxogenated by Co, 501, Cu 518, Fe 
506, Ni 423, 424, Pd 548, 558, Pt 
342,527 

polymerized, 212, 914 
Acetylene bond, migration of, 192 
Acetylene compoimds hydrogenated, 
423-125, 518, 527, 548, 558, 566, 
577, 601 
Acetylene glycols hydxogenated, 548, 

566,577 
Acetylene hydrocarbons decomposed, 
913-919 

hydrated, 308 

polym., 212 
Acetylene tetrabromide, 289, 897 
Acetylene tetrachloride, 199 
Acetyl-yanilline hydxogenated, 568 
Add amides hydxolyied, 331 
Add anhydrides formed, 872 

hydxogenated, 392 

into ketones, 857 
Add chlorides, 243 

with ammonia, 813 

decomposed by AlCU , 625 

in F. and C. reaction, 891-894 

hydrogenated, 575 
Adds, in formation of acetals, 783 

from alcohols, 150, 246, 275 

catalysts, 17, 81 

decomposed, 171, 820-856 

in depolymerisation, 234 

in eeterification, 748-756 

hydrogenated, 422 

in hydrolysis, 175, 305 

in hydrolysis of glucoddes, 175 

in inverdon of sugar, 175 

in isomerisation 181-182 
Aconitic add hydrogenated, 558 
Acridine hydrogenated, 491 

oxidised, 270 
Aeridone, 270 



Acrolelne, 101, 249, 658, 680, 713, 725, 
726 

hydrogenated, 419 
Acrylic add hydrogenated, 417 

by oxidation, 249 
Activated charcoal as catalyvt, 28291 
Active alkaloids as catalysts, 836 
Active modifications, 180i 
Adipic add, 251 
Adsorption theory, 180e 
Aeration of Pt. black, 563 
Agitation in catalsrsis, 541 

in hydrogenation, 957 
Albumin, stabiliser for, Pd, 69 
Alcohol eliminated, 817 

as source of H, 537 

as solvent in hydrogenation, 599 

toxic to Pt. bUck, 117 
Alcoholates, 299 
Alcohols with aldehydes, 784 

decomposed, 180g, 538, CdO 674^ 
C 679, SnO 673, Zn 678 

dehydrated, 28, 75, 98, 99, 138, 180A 

dehydrogenated, 28, 650-679 

by hydration of hydrocar., 305 

hydxogenated, 416 

oxidised, 246, 249, 254, 268 
Alcohols, aromatic, hydxogenated, 369, 

465 
Alcohol3rBis, 340, 340n 
Aldehydes, 236, 653, 655, 668, 701, 723 

acetylated, 240 

into acetals, 780-783 

from alcohols, 15, 48, 246, 650 

condensed, 90, 237, 239, 240, 794- 
810 

crotonised, 794-801 

decomposed, 618-623, 532, 549 

dehydrated, 794r^802 

by depolymerisation, 234 

into esters, 225-228 

formed, 15, 28, 31, 48, 75, 142, 200, 
208.866 

hydrogenated, 388. 419, 432-434, 
568, Co 503, Cu 522, Fe 506, 593, 
Ni 588, 602, Pt 567 

by oxidation, 15, 48, 258-261, 268, 
275 

from oximes, 268, 332 

with phenols, 792 

polymerised, 82, 106, 218-228 



SUBJECT INDEX 



387 



preparation of, 851-854 
Aldolisation, 82, 83, 95, 97, 219, 221 
Aldols depolymerised, 234 

formed, 219 
Aldoximes dehydrated, 814 

hydrogenated, 383, 384, 514 

iaomerized, 204 
Alicydio ketones hydrogenated, 436 
Aliphatic hydrocarbons cracked, 911, 

912 
Alisarine, 274, 328 
Alkalies in hydroljrsiB, 305 
Alkaline bisulphates in esterif., 748, 
759, 760 

carbonates as oats., 97 

halides elim., 904 
Alkaloids as cats., 836 
Alkyl-anilines, 729 

Alkylation of arom. hydrocar., 884-890 
Alkyl bromides decomposed, 876 

in F. and C. syn., 885 

in Grignard reliction, 302 

isomerised, 199, 200 
Alkyl chlorides decomposed, 86, 876- 
882 

in syn., 883^^9 
Alkyl haUdes, 104, 300^304, 883-885 

iaomerized, 876 
Alkyl iodides, 304 

decomposed, 876 

in F. and G. reaction, 885 
Alkyl phenol ethers, 494, 789 

hydrogenated, 464 
Alkyl piperidines, 741 
Alkyl sulphides, 626-628, 743, 744 
Alkyl ureas, 431 
Allenic hydrocarb. hydrated, 308 

isomerised, 192 
AUyl alcohol 601, 680, 740 

dehydrated, 713 

esterified, 757 

isomerised, 208, 658 

oxidised, 249 

hydrogenated, 416, 558 
Allyl amine as cat., 836 
Allyl bensoate, 766 
AUylene hydrated, 309 

polymerized, 212 
Allyl iodide, 605 
Allyl ketones hydrogenated, 602 
Allyl mercaptan, 744 



Ahnond oil, 938 
Alumina as carrier, 127 

as catalyst, 75, 78, 169, 18Q;, 540, 
586, 624, 676, 693, 694, 700, 714, 
721, 722, 732, 740, 784, 797n, 807- 
814, 825 

in cracking, 906, 934 

decomp. chlorides, 881 

decomp. esters, 861n, 866, 872-874 

decomp. hexane, 920 

dehydration catalyst, 142, ISOg, 
180A, 651, 686, 743, 784, 791 

esterification cat., 764 

isomerises unsat. hydroc., 190, 200 

ketone cat., 840, 849 

life of, 708 

mercaptan cat., 746 

polymeris. unsat. hydroc., 211 

preparation of, 77, 706, 713, 714 
Aluminum cat., 284, 886, 901 

in cracking, 906 

dec. hydrocarb., 920 

influence on, Pd, 946 
Aluminum alcoholates, 12, 299 

amalgam, 293 

catalyst, 51 

dissolved in alcohols, 12 

oxidation cat., 254 
Aluminum bromide, bromination cat., 
93,293 

catalyst, 298 

chlorination cat., 289 

isomeriz. cat., 119 

in F. and G. reaction, 893 
Aluminum chloride, bromination cat., 
293 

with carbon monoxide, 298 

catalyst, 6, 33, 87, 173-174, 239-243, 
293-297, 687, 728, 795, 797, 803, 
806, 817-819, 877-^79, 884-900, 
903, 929-931, 935 

chlorination cat., 283, 284 

condensation cat., 903 

cracking cat., 935 

on cymene, 930 

dehydrogenation cat., 638, 685 

in F. and G. reaction, 896-900 

on hydrocarb., 929-931 

on naphthalene, 931 

on pinene, 931 

polymerises hydrocarb., 211, 216 



368 



SUBJECT INDEX 



regenerated, 035 

in sulphonation, 296 

with sulphur dioxide, 207 

theory of action, 173, 687, 728 

on thiophenol, 020 

on xylene, 030 
Aluminum ethylate poljrmer. aids., 228 

preparation, 290 
Aluminum phosphate, 00, 710, 726 
Aluminum powder cat., 001 
Ahiminum salts dehydration oat., 717 

in nitration, 260n 
Aluminum sulphate cat., 00, 606, 706, 

717, 726, 760, 760 
Aluminum turnings chlorination oat., 
284 

in F. and C. reaction, 886 

with mercuric chloride, 886 
Amarine formed, 104 
American hardened oils, 067n 
American petroleum, 008, 028, 032 
Amides d^ydrated, 811 

hydrogenated, 386, Cu 614, Ni 386 

hydrolised, 306, 311, 331, 336, 336 

from nitriles, 311 

from oximes, 204, 206 

polymerised, 233 

syn. by F. and G. reaction, 806 
Amines, 170, 426, 480, 431, 613, 614, 
600,682 

oond. cat., 803 

deoomp. Ni, 681 

dehydrogenated, 681, 682 

formed, 16, 170, 382, 383, 731-742 

hydrogenated, 406 

by hydrogenation, 382, 383 

oxidised, 268 

from oximes, 383 

secondary, 682 

suphurised, 206 

syn. of, 683, 731-742 

in vulcanis. of rubber, 104 
Amino-aoetophenone, 646, 667 
Amino-benzoic add hydrogenated, 660 
Amino-caproic add into lactam, 206 
Amino-cydo-hexanes dehydrogenated, 

642 
Amino-cyclo-hexane-oarbonic add, 660 
Amino-ethyl alcohol oxid., 268 
Amino-malonic nitrile, 230 
Amino-naphthol, 664 



Amino-nitrobeniene, syn. of, 901 
Amino-phenol, 630, 632 
Amino-phenols, 381, 636 
Amino-flucdnio add, 312 
Ammonia into amines, 001 

condensed with aids., 807-^00, 812, 
813 

condensed with ketones, 800 

condensation oat., 803, 804 

in cracking, 033 

deoompodtion oat., 637 

diminated, 611, 631-633 

with esters, 871 

by hydrogenation, 377 

from nitric oxide, 368, 374 

oxidised, 240, 266 

polymeria cat., 104 

syn. of, 1808, 180e, 180u, 342 
Ammonium alum, 784 
Ammonium diloride oat., 07, 783 
Ammonium isosulphocyanate, 104, 207 
Ammonium nitrate, 07, 266, 376, 376 

783 
Ammonium nitrite, 376 
Ammonium salts in esterif ., 748 
Ammonium sulphate, 07, 783 
Amount of catalyst, 608, 061 
Amoimt of adds in esterif., 763-766 
Amphoteric hydroxides, 860 
Amygdalin, 320 
Amyl-amine, 486, 631, 681 
Amyl alcohol, 160, 673 
Amyl-bensine hydrog., 660 
Amylene, 626, 606, 746, 871, 020 

dec. by AlCU, 020 

hydrated, 306 

hydrogenated, 668, 666 

preparation of, 706n 
Amyl nitrite, tox. to cats., 116 
Amyl oleate hydrogenated, 626 
Amyl stearate, 626 
Anethol hydrc^nated, Ni 600, 601 
Anhydrides hydrogenated, 302 
Aniline, 460, 406, 407, 631, 636, 638, 
646, 664, 667, 676, 630-632, 683, 
790 

alkylated, 720, 740 

eliminated, 634, 636 

formed, 166, 277, 378, 380, 381 

hydrogenated, 466, 467, 660 

by hydrogenation, 277, 378, 380. 381 



SUBJECT INDEX 



369 



manufactuie, 378, 511 

methylated, 729 

oleate hydrogenated, Ni 601 

oxidi8ed,256 

in syn., 001 

toxicity to cats., 116 
Aniline black, 260fi, 271 
Aniline hydrobromide as oat., 726 
Anilines, substituted, 468 
Animal charcoal, carrier, 946 

catalyst, 48, 282 
Anisalcohol, 568 
Anisaldehyde condensed, 806 

hydrogenated, 568 

polymerised, 220 
Anisdidines, 632 
Anisolne, 220 
Anisol condensed, 806 

hydrogenated, 464, 494, 589 

neg. oat., 11, 303 

preparation, 789 
Anthracene, 274, 806, 897, 908, 909, 
914, 921 

from acetylene, 914 

condensed, 806 

by cracking, 908, 909 

decomposed, 921 

by F. and C. reaction, 897 

hydrogenated, 29, 363, 483, 592 

oxidised, 257, 260fi, 262, 262n, 269, 
271 
Anthracene blue by oxide., 274 
Anthracene hydrides dehyd., 642, 728 
Anthraquinone, 257, 260n, 262, 262n, 
269, 271, 839, 846 

sulphonated, 816 

qm. by F. and C, 893 
Anthraquinone disulphonic adds, 816 
Anthraquinone sulphonic acids, 816 
Antimony cat., 47 
Antimony chloride cat., 90, 216 

chlorination cat., 283, 287 

in F. and C, 899 
Apparatus for dehydration, 717 

for dehydrogenation, 654 

for hydrogenation, 584, 585, 597, 
957-964 
Arabinose dehydrated, 727 

from ECHO, 221 

multirotation, 188 
Arabite oxid., 268 



Araboketose by oxid., 268 
Arab<»uc add, 187 
Arachidic esters, 937 
Arbutin hydrolysed, 328 
Argon abs. by C, ISOd 
Aromatic adds dec., 830 

esterified, 758, 766 

hydrogenated, 471 
Aromatic alcohols condensed, 728 

hydrogenated, 369, 465 

reduced, 360 
Aromatic aldehydes hydrogenated, 388, 

568 
Aromatic amides syn. by F. and C, 

895 
Aromatic amines with alcohols, 740 

hydrogenated, 466 

syn., 901 

thioureas, 630 
Aromatic bromides from diaso., 608 
Aromatic chlorides from diaso, 607 
Aromatic ethers, 494 
Aromatic hydrocarbons from CtHi, 926 

alkylated, 877-890 

brominated, 291-293 

by cracking, 932 

decomp., 921, 930 

hydrogenated, 446 

oxidised, 269 
Aromatic ketones hydrogenated, 389| 

455, 523, 590 

Aromatic nitro-compe. hydrogenated, 

511.600 
Aromatic nucleus hydrogenated, 444- 

456, Cu 594, Fe 593, Ni 589, Pd 
556, 578, Ft 534, 560, 569 

Aromatic rings hydrogenated, 444-456, 

534 
Arsenic toxic to Ft, 116 
Arsenic add, 691 
Arsenious oxide toxic to Pt, 116 

transformed, 73 
Arsine cat. poison, 180o 

decomp. of, 8 
Asbestos as carrier, 126, 941 
Asparagine formed, 312 
Aspartic imide hydrogenated, 312 
Asymmetric dec. of adds, 836 
Atoms, migration of, 199 
Auto cataljTsis, 8 
Autoclave for, Ht, 597 



370 



SUBJECT INDEX 



Auto oxidation, 160, 161 
Aiobeniene, by hydrogenation, 611 

hydxogenatedi 497, 664 
Aio-compounds hydrogenated, 600 
Aioxy-oompoundB hydrogenated, 600 

Bakelite,792 
Baku petroleum, 444 

oradced, 034 
Barium oarbonate oat., 08, 838 
Barium chloride oat., 86, 876, 880 
Barium hydroxide eond. agt., 800 
Barium peroxide poly, cat., 214 
Barium salts deoomp., 837 
Barium soaps neg. cat., 116 
Bases as cats., 83 

in hydrolysis, 176, 178 
Bauxite cat., 706, 706n 
Beef tallow, 038 
Benial-acetone, 798 
Bensal chloride, 320, 890 
Bensaldehyde, into acetal, 783 

aoetalated, 240 

from bensal chloride, 320 

condensed, 89, 796, 799, 803, 804, 
807,808 

decomposed, Ni 620, Pd 623 

into ester, 225 

formed, 166, 676, 667, 674 

by F. and C. react., 297, 298 

by hydroljTsis, 329 

by oxidation, 249, 267, 259, 260n, 268 

hydrogenated, Fe 693, Ni 388, Pd 
549, 660, Pt 668, thoria 638 

polymerised, 220 
Bensaldoximes transformed, 186 
Bensamide by F. and C. syn., 896 
Bensanthrone, 686 

Bensene, 618, 693, 620, 641, 643, 649, 
667, 674 

from CtHt, 914-916 

brominated, 292 

chlorinated, 278, 284, 286 

oondensed, 806, 817-819 

by cracking, 908, 909 

in cracking, 907 

from (^ymene, 930 

decomposed, 907, 921 

in F. and C. syn., 894, 897 

in Grignard syn., 300 

hydrogenated, 26, 344, 361, 362, 



444-147, 634, 589, 947n, Co 502, 
Pt 660, 669 

from hydrogenation, 370, 378, 388 

neg. cat., 11 

oxidised, 260fi, 263, 268, 276 

sulphonated, 816 

from xylene, 930 
Bensoie homdoQB from acetylene, 618 

hydrogenated, 447-460, Co 502, Pt 
569 
Bensene ring hydrogenated, Ni 603 
Bensoie sulphinic add, 297 
Benshydrol, 638, 728, 745 

to amine, 736 

dehydrated, 688, 692, 720 

dehydrogenated, 650, 662, 720, Pd 
669 

hydrogenated, 369 
Benshydryl amine, 736 

mercaptan, 745 
Bensidene, 202 
Bensoic add from aldehyde, 226 

into aldehyde, 853 

from benaotrichloride, 320 

decomposed, 830, 834, 839, 840^845 

esterified, 757, 758, 766, rate 768n 

hydrogenated, Ni 590, Pd 561, Pt 
559,660 

into ketone, 848-850 

by oxidation, 257 

sulphonated, 816n, 816 

from toluene, 160 
Bensoic esters, decomp., 864 

hydrogenated, 471 
Bensolne, 220, 234, 690 

hydrogenated, 391 
Bensonitrile by dehydration of amine, 
681 

by diaso reaction, 606 

from esters, 871 

hydrogenated, 428 

polymerised, 232 
Bensophenone, 638, 650, 662, 669, 
720, 845, 846, 890 

condensed, 809 

formed, 839, 891, 893, 899 

by F. and C. syn., 891, 893, 899 

hydrogenated, 389, 539, 590, Cu 
623, Pt 560 
Bensophenone oxime, 384 
Bensotrichloride, 320 



SUBJECT INDEX 



371 



Benioyl««oetone hydrogenated, 391 
Bensoyl-bencoio acid, syn. of., 893 
Benzoyl chloride in F. and C. syn.^ 
893,899 

hydrogenated, Pd 675 

into nitrile, 813 
Benzoyl peroxide cat., 214 
Benzoyl-propionic acid, 203 
Benzoyl-salicylic aid. hydrogenated, 568 
Bensoyl-vanilline hydrogenated, 5d8 
Benzyl-acetone hydrogenated, 389 
Benzyl alcohol, 549, 560, 715, 729, 740 

from aldehyde, 225 

into amine, 734 

cat. solvent, 38 

condensed, 728 

dehydrated, 688, 714 

dehydrogenated, CdO 674, Cu 657, 
Mn0 673 

esterified, 771, 773 

hydrogenated, 369, 465, 538, 593 

oxidised, 249 
BeniQrl amine, 428, 631, 734 

catalyst, 836 

dehydrogenated, 681 

hydrogenated, 470, 496, 560 
BeniQrl-aniline, 729 
Benzyl-benzylidene-aoetone, 547 
Benzyl chloride dechlorinated, 605 

decomposed, 880, 916 

formed, 281, 818, 889 

in F. and C. syn., 889 

in syn., 899, 901 
BeniQrl cyanide, 605, 871 
Bensyl-cydohexyl-amine, 739 
Benzyl formate, 773 
Benzylidene acetate formed, 240 
Beni^Udene-hydrindone, 799 
Benzyhdene-malonic acid, 804 
Benzyl mercaptan, 744 
Benzyl-pyridines syn., 901 
Beryllia cat., 651, 675, 676, 702, 778, 828 

esterific. cat., 778 
Betulol hydrogenated, 570 
Bi-cyclo-octane, 480 
Bi-oydo-octene hydrogenated, 480 
Bis-diasoacetic acid hydrol., 332 
Bismuth oxidised, 269n 
Bleaching of oils, 265 
Blue oxide of molybdenum cat., 675, 
732,827 



dehydration cat., 791 

mercaptan cat., 746 
Blue oxide of tungsten cat., 651, 676, 
693, 700, 702, 708, 709, 715, 716, 
732,825 

dehydration cat., 791 

mercaptan cat., 746 

preparation of, 715 
Boric add dec esters, 864 

dehydration cat., 687 

influence in hydrogenation, 944 

oxidation cat., 274 

toxic to cats., 115 
Boron fluoride polymer, cat., 84, 211 
Bomeol from acetate, 340 

from camphor, 591, 722 

dehydrated, 714 

dehydrogenated, 661 

esters of, 340 

oxidised, 257, 260n 
Bomyl acetate, 340 
Brands of hardened fats 967, 967n 
Brass cat., 254n, 670 
Brass block furnace, 348 
Brassidic add formed, 184 

into ketone, 843 
Brochet's apparatus, 597 
Bromal cond., 806 
Bromanilines red., 405 
Brombensene formed, 292, 293 

hydrogenated, 405, 545 

sulphonated, 815n 

in syn., 901, 904 
Brombensoyl chloride in F. and C. syn., 

893 
Bromides cats., 84 
Bromination, 290-293 
Bromine, cat., 43 

chlorination cat., 279 

dim., 405, 407, 605 

isomerisation cat., 182 

toxic to cats., 116, 359 
Bromnaphthalenes isom., 199 
Bromnitrobenzenes hydrogenated, 405, 

512 
Bromst3nrene hydrogenated, 546 
Bromtoluene, 293, 405 
Brudne hydrogenated, 555 
Butadiene formed, 726, 784 

polym., 213 
Butaneal-ol (1, 3) formed, 219 



372 



SUBJECT INDEX 



Butane, 473, 621 
Butanediol dehydrated, 736 

hydxogenated, 438 
Butaaol-one, 438 
Butanone hydrogenated, 435 
Butylene, 776 

Butyl alcohol from orotODio aid., 419, 
£67,801 

dehydrated, 700, 713, 719 

dehydrogenated, 666, 664 

esterjfied, 771, 773 

oxidised, 249, 268 
aec. Butyl alcohol dehydrated, 713 

dehydrogenated, 666 
tert. Butyl aloohd dehydrated, 713 

esterified, 776 
Butyl-beniene hydrogenated, 448, 660 

by hydrogenation, 380, 301 
Butyl benioate, 766 
tert. Butyl bromide, 200 
Butylene from acetylene, 916 

by dehydration, 670, 606, 713 
Butyl formate, 773 
tert. Butyl ieocyanate, 430 
Butyl mercaptan, 744n 
Butyl-naphthalene by hydrog., 390 
Butyl-phenol hydrogenated, 459 
Butyric add from crotonic, 422 

decompoaed, 839 

CBterified, 771 

into ketone, 840, 842-844, 846 
Butyric aldehyde from BuOH by Ni, 
664 

from PKXKa, 575 

from crot. aid., 419, 567 

crotonised, 795 

dec. by Pd, 623 

by oxidation, 249 

polymerised, 223 
Butyric cBters decomp., 863, 871 
Butyrolactone by hydrogenation, 392 
Butyryl chloride hydrogenated, 575 

Cadmium dehydrogenation cat., 674, 
824 
ketone cat., 841 
Cadmium chloride cat., 876 
Cadmium oxide dehydrogenation cat., 
674, 676 
dec. formic ac., 539 
ketone cat., 841, 849 



Cadmium sulphate cat., 626 

Calcium carbamate in acetone prep., 161 

carrier for cat., 127 

caUlyst, 98 

ketone cat., 161, 838, 839, 849, 857 

to neut. oils, 848 
Caldum hydroxide toxic to cats., 116 
Caldum oxide cat., 83, 98 

decomp. hydrocarfo., 911 

ketone cat., 840, 849 
Caldum salts cats., 269n 

decomposed, 837 
Caldum sulphate cat., 98, 687, 718 
Camphane, 477, 552, 594, 611, 722 
Camphane from bomeol, 722 

dehydrogenated, 644 

hydrogenated, Cu 594, Ni 477, 591, 
Pd 552, Pt 570 
Campholide by hydrogenation, 392 
Camphor from bomeol, 260n, 269n, 661 

hydrogenated, 591, 722 

by oxidation, 257, 260n, 269n 
Camphor adds, 836 
Camphor-hyraaone dec., 611 
Camphoric add by oxid., 257 
Camphoric anhydride hydrogenated, 

392 
Camphorone hydrogenated, 421 
CamphoiHudme hydrogenated, 385 
Cane sugar oxidised, 269 
Candelite, 967 

Caoutchouc, syn. of, 214, 215 
Caproic acid into aldehyde, 853 

esterified, 771 

into ketone, 845 
Caproic aldehyde, 853 
Caproic esters decomp., 871 
Caprylic add into ketone, 843 
Caprylene hydrogenated, 414 
Carbamic chloride in F. and C. sjm., 

895 
Carbazol hydrogenated, 490 
Carbides in earth, 928 
Carbimides, 431 

Carbohydrates hydrogenated, 595 
Carbon catalyst, 48, 49, 257, 257n, 
687, 700, 811, 828, 911 

cat. dec. alcohols, 679 

dehydrogenation cat., 638, 679 

hydrogenated, 409, 525, 586 

oxidation cat., 257 



SUBJECT INDEX 



373 



separated, 613 
Carbon dioxide eliminated, 831 

hydfogenated, Co 504, Cu 508, Ni 
396, 396, 586, Pt 533 
Carbon disulphide chlorinated, 283 

eliminated from ill. gas, 339, 372 

on F. and C. syn. 892, 893, 897 

hydrogenated, 372, 492 

hydrdyced, 339 

negative cat., 303 

reduced, 372 

into thioureas, 630 

toxic to cats., 116 
Carbon hexachloride formed, 289, 881 
Carbon monoxide, 508, 593, 613-617, 
821, 825^28, 866-869, 953 

added, 298 

decomposed, 163, 614 

eliminated, 618^25 

from formic acid, 143, 172 

in F. and C. syn., 297, 298 

hydrogenated, 540, Co 504, Ni 393, 
394, Pd 536, Ft 533 

in hydrogenation, 953 

oxidised, 150, 180a, 248, 251 

source of H in hydrogenation, 537 

toxic to cats., 116, 180o 
Carbon suboxide, 873 
Carbon' tetrachloride added, 242 

formed, 1806, 278, 279, 282-285, 
287 
Carbylamines hydrogenated, 430, 521 

hydrolysed, 334 
Carbonyl chloride in F. and C. ^yn., 
891, 893 

polymerise aids., 222 

preparation, 134, 282, 282n 
Carbonyl group hydrogenated, 432-442 
Carboxy-camphor adds, 836 
Carriers for oats., 126, 941, 946 
Carvaorol hydrogenated, 459 
Carvacrylene, 789 
Carvaoyl ethers, 786, 789 
Canromenthane, hydrogenated, 570 
Carvomenthol, 567, 722 
Carvomenthone, 591 
Carvone hydrogenated, 476, 552, 567, 

591 
Carvotenaoetone, 567 
Caryophylene hydrogenated, 560 
Castor oO in alcoholysis, 341 



hydrogenated, 968 

iodine no., 938 
Catalysis, definition, 1, 3, 4, 140 

at a distance, 18Q; 

history of, 4 

mechanism of, 129-180u 
Catalysts, amounts of, 32, 951 

for cracking, 906, 910-912 

dehydration, 687 

hydrogenatiim, 598, 941 

life of. 111, 359, 947 

orienting, 816 

placing in tubes, 128 

poisons for, 112, 113, 116, 359, 946 

preparation, 54-56, 58, 59, 76-78, 
598, 606, 655, 704, 705, 707n, 
861n, 941, 942 

regeneration of, 947fi, 950 
Caucasian petroleum, ^26 
Cellulose hydrdysed, 323 
Ceria in drying oils, 266 

ketone cat., 849 

oxidation cat., 259, 261 

promoter, 180< 
Cerium compounds cats., 153, 264, 

269n,271 
Charcoal as absorbent, ISOd, I8O9 

animal as carrier, 946 

animal as cat., 282n, 700 

carrier for, Ni 598, 941, 946 

catalyst, 828 

chlorination cat., 282 

cat. for phosgene, 282n 

condenses gases, 131, 135 

dec. hydrocarb., 911 
ChemiciJ potential, 180^ 
Chemical theory of cat., 145 
Chloracetanilid, 202 
Chloracetates reduced, 407 
Chloracetio acid, 280, 281 
Chloral cond., 239, 806 

polymer., 224, 228 
Chloranilinee, 512, 632 
Chlorates oxidisers, 271 

reduced by Pd, 165 
Chlorbenienes formed, 278, 284, 285, 
404 

sulphonated, 815n 

in syn., 904 
Chlorbenioio acid hydrogenated, 545 

in syn., 901 



374 



SUBJECT INDEX 



Chlorbensoyl chloride in F. and C. 

syn., 893 
6>-Chlorbutyl-benflene in F. and C. 

syn., 897 
Chlorcaffelne hydrogenated, 545 
Chlorcinnamio ac. hydrogenated, 245 
Chlor-compounds hydiolyied, 320 
Chlorcrotonic add hydrogenated, 545 
Chlorcydo-hexane, 4iOS 
/S-Cfalorethyl-benxene in F. and C. 

ayn., 897 
Chlorides cats., ^ et eeg. 
Chlorides cfalorination oats., 278 

oxidation oats., 263 
Cfalorination, 44, 58, 90, 156, 278-289 

of aoetio add, 280 

oatalyste, 283-285 
Chlorine absorbed by C, 180& 

catalyst, 43 

eliminated, 403, 404, 407, 605 

produced, 103 

toxic to cats., 359, 947 

on water, 257n 
Chlorketones produced, 243 
Chlormethyl ethers cond., 818 

in F. and C. syn., 889, 899 
Chloi^trobenxenes hydrogenated, 404, 
512 

in syn., 901 
Chlor-nitrobenaoic add in 83m., 901 
Chloroform cond., 238 

formed, 629, 879 

in F. and C. syn., 890 

negative cat., 11, 238 

stabilised, 11 

in syn., 890, 903 
co-Chlorpentyl-benxene in F. and C. 

syn., 897 
Chlorphenols by reduction, 404 
Chlorpicrin, 180g 
Chlortoluene hydrogenated, 569 
Cholesterine hydrogenated Ft, 565 
Chromic chloride, 357 
Chromic oxide, cat., 75, 675, 676, 693, 
703, 732, 746, 791, 840, 849 

dehydration cat., 702, 791 

dehydrogenation cat., 686 

in drying oils, 266 

ketone cat., 840, 849 

mercaptan cat., 746 

mixed cat., 702 



oxidation cat., 259 

preparation of, 78 
Cinchonidine hydrogenated, Pd 555 
Cinchonine hydrogenated, Pd 555, Pt 

561 
Cinchotine, 555 
Cineol dehydrogenated, 645 
Cinnamene hydrogenated, 451 
Cinnamic add esterified, 756, 757 

formed, 107, 246 

hydrogenated, 417, 581, 583, 604, 
Cu 594, Ni 590, 601, Ru 580 

by hydrogenation, 548 
Cinnamic alcohol oxidised, 249 
Cinnamic aldehyde from alcohol, 246 

condensed, 799 

hydrogenated, Pd 546, Pt 568, 560 

by oxidation, 249 
Citraoonic add hydrogenated, Pt 558 

isomeriied, 183 
Citral condensed, 800 

from geraniol, 658 

hydrogenated, Pd 595, Pt 567 
Citric add esterified, 756 

retarder, 11 

toxic to cats., 115 
Citronellol, 416 

Class of alcohol determined, 701 
Clay dehydration cat., 99, 700, 702, 717 
Clarif3ring solutions, 257n 
Qupadonic add, 937, 938, 955 

esters of, 937 
Coal oxidation cat., 257 
Cobalt on alcohols, 666 

catalyst, 57, 167, 615 

in cracking, 906 

decomp. CsHi, 919, 920, 928 

decomp. aromat. hydrocarb., 921 

decomp. hydrocarb., 906, 912 

dehydrogenation cat., 637, 651, 652, 
666 

deterioration of, 500 

hydrogenation cat., 344, 499-504, 945 

in drying oils, 266 

oxidation cat., 254, 258 
Cobalt carbonyl,'616 
Cobalt chloride cat., 283, 876 
Cobalt oxide, oxidation cat., 75, 1800, 

259 
Cobalt soap, 265 
Cocoa butter, alcoholysis of, 341 



SUBJECT INDEX 



375 



hardened, 066 

iodine number, 038 
Coooanut oil, hydiogenated, 039 
Codeine, hydrogenated, Pt 572 
Codliver oU, hardened, 066 

iodine number, 038 
Coke as catalyst, 48, 257 
Colchicine hydrogenated, Pd 555 
Collidines, 686 

Collisions of molecules, 1808, 18Qf 
Colloidal metals, preparation of, 67 
Colloidal palladium, 544->655, 604 
CoUoidal platinum, 544, 556^661 
Colophene from pinene, 216 
Colsa oil, 038 

Complex rings hydrogenated, Pt 571 
Condensation of aldehydes, 704-800 

of ketones, 704-800 
Coniferine hydxol., 320 
Comferyl alcohol by hydiol., 320 
Contact process, 180r, 258 
Contrarvalencies, ISOh 
Copper catalyst, 50, 260n, 538--540, 
683, 602, 824, 831, 833-835, 001, 
004,020-022 

on alcohols, 142 

colloidal, 72 

in cracking, 006, 032 

decomp. CtHs, 013, 016, 017, 020 

decomp. aldehydes, 621 

decomp. CO, 615 

decomp. formic esters, 867 

decomp. hydrocarb., 021 

decomp. pinene, 022 

dehydrogenates amines, 681 

dehydrogenation cat., 142, 636, 637, 
641, 646, 651-654, 656-4(63, 680, 
681, 701, 720, 726, 824 

on diazo-compe., 606-610 

hydrogenation cat., 344, 507-i623, 
504, 030, 045 

isomer, cat., 208 

oxidation cat., 15, 75, 162, 167, 
253, 254, 258 

preparation, 50, 606, 655 
Copper chloride cat., 635 
Copper oxide cat., 250, 260n 
Copper powder cat., 606-610, 655 
Copper salts in nitration, 260n 

in oxidation, 271 
Copper sulphate cat., 240, 272, 725 



in Deacon's proc., 103 
Cottonseed oil, iodine number, 038 

hydrogenated, 587, 065, 067n 
Counumio add dec., 835 
Cracking, 006, 010-012, 020-^36 

by AlCli, 020^031, 035 

by cats., 010-012, 032, 034 

disGOveiy, 006 

with oxide cats., 034 
Cresol ethers hydrogenated, 404 
Cresols with aldehydes, 702 

ethera of, 386, 785, 786, 780 

formed, 386, 645, 660 

hydrogenated, 457, 464 

by oxidation, 263 
Cresyl-carvaoryl ether, 788 
Cresyl-diamines by hydrogenation, 380 
Cresyl oxides, 785 
Cresyl-propanes hydrogenated, 415 
Crisco, 067n 
Crotonic acid into aldehyde, 853 

esterified, 756, 771 

hydrogenated, 422, Pd 546, Pt 558 
Crotonic aldehyde, 307, 704-706, 801 

condensed, 706 

formed, 52, 210, 308, 310 

hydrogenated, 410, Pt 567 
Crotonisation, 81, 80, 107, 704-800 

of aldehydes, 705 

of ketones, 707 
Crotonylene polym., 212 
Cumene, 644 
Cuminio aldehyde by oxidation, 240 

polymerised, 220 
Cuminolne, 220 
Cuminyl alcohol oxid., 240 
Cuprene, 518, 016-018 
Cupric hydroxide purif . of oils, 048 
Cuprous bromide cat., 608, 611, 633 

in diaao reaction, 01 

prep., 608 
Cuprous chloride cat., 208, 611, 633, 
870, 001 

in diaso reaction, 01 
Cuprous iodide cat., 611, 001 

in diaso reaction, 01 
Cuprous oxide in diaso., 01 
Cuprous salts cats., 611, 633 

in diaao reaction, 606-610 
Cyanethine, 232 
oats., 05 



376 



SUBJECT INDEX 



Cyanogen hydrated, 312 
Cyaphenine, 232 
Cyclic addB dec., 830 
Cyclic hydrocarb. dec., 921 

polym., 216 
Cyclic ketones, 611 
Cyclic ketozimes, 206 
C^clisation, 82, 194 
Cydo-aliphatic ethefs, 404 
Cyclobutane, 473 
C^dobutene hydrogenated, 478 
Cydobutene bromide, 203 
Cydoheptane, 197, 479, 649 
Cydobexadienes dehydrogenated, 643 
C^clohexadiolB, 461 
C^do-hexadione, 874 
Cydo-hexamethylene ring, 476 
Cydohexane, 445, 452, 466, 468, 469, 
471-475, 497, 534» 560, 587, 589, 
611, 643 

decomp., 921 

dehydrogenated, Fe 593, Ni 641 

formed, 26, 55, 113, 361, 388, 389, 



oxidised, 251 

prepared, 446 

purified, 446 
Cydohexane alcohols, 698, 737 
Cydohexane hydrocarb. dehydrogen« 
ated,641 

formed, 389 
Cydohexane petroleums cracked, 934 
C^dohexanol, 30, 120, 443, 460, 461, 
560, 569, 589, 603, 739, 741 

into amine, 737 

dehydrated, 714 

dehydrogenated, 642, 660 
Cydohexanol homologs dehydrogenated, 

642 
Cydohexanone, 456, 560, 642, 660 

crotonised, 797 

hydrogenated, 436, 567 

hydrasone, 611 

oxime hydrogenated, 385 
Cydohexatriol, 462 

Cyclohexene, 456, 475, 515, 628, 643, 
698, 714 

dehydrogenated, 643 

hydrogenated, 587 
Cydohexene acetic add hydrogenated, 
476 



Cydohexendiol ether, 443 
Cydohexanes by dehydration, 696 

dehydrogenated, 643 
Cydohexanol by oxidation* 251 
Cydohexenone hydrogenated, Pd 552 
Cydohexyl-acetic add, 471, 476 
Cydohexyl alcohols dehydrogenated, 

714, 717 
eeterified, 757, 766 
Cydohexyl-amine, 466, 469, 497, 560, 

560, 737, 739 
dehydrogenated, Ni 642 
by hydrogenation, 378, 385 
Cydohexyl-amines, 739 
C^dohexyl-aniline, 466, 469, 642 
Cydohexyl benioate, 766 
Cydohexyl chlmdee deoomp., 876 

in F. and C. syn., 889 
Cydohexyl-cydohexene hydrogenated, 

475 
Cydohexyl-diethyl-amine, 468 
Cydohexyl-ethyl-amine, 468 
Cydohexyl-heptane by hydrogenation, 

414 
Cydohexyl mercaptan, 628, 745 
Cydohexyl-methyl-amine, 468 
Cydohexyl oxide, 589 
Cydohexyl piperidine, 741 
Cydohexyl-propifHiio add, 471, 580 

581,590 
Cydohexyl-propyl alcohol, 560 
CydoheaQrl sulphide, 628 
Cydo-octadiene, 480 
Cydo-octane dec. Ni, 197 

by hydrogenation, 480, 571 
Cydo-octanone, 571 
Cydo-ootatetrene hydrogenated, 535, 

571 
Cydo-ootatriene hydrogenated, 571 
Qrdo-octenone hydrogenated, 571 
Cydo-paraffine oximes hydrogenated, 

385 
Cydopentadiene hydrogenated, 474 
Cydopentane, 436, 474, 649 
C^dopentane-carbonic add, 649 
Cydopentanol, 436 
Cydopentanone, 874 
hydrogenated, 436, 567 
oxime hydrogenated, 385 
Cydopentyl-^mines by hydrogenation, 

385 



SUBJECT INDEX 



877 



Cydopental-benieiie by F. and C. nyn., 

897 
Cycbpentyl ohloridM dec., 876 
C^dopentykgrdopentanone, 436 
C^dopropane hydrogeoated, 472 
Cydopropane ring dec., 193 
Cymene dee. by AlCk, 930 

by dehydrogenation, 644, 646 

hydro^nated, 448 

from pinene, 922 
Cymenea by hydrogenation, 369, 416 

Deaoon'8 prooeas, 103, 180&, 267n 
Decahydro-aoenaphihene, 663 
Decahydro-anthraoene, 692 
Decahydro-fluorene, 464 

dehydrogenated, 642 
Decahydro-naphthakne, 481, 663, 671, 

692, 694 
Decahydro-naphthob, 481, 692, 714 
Decahydio-quinaldine, 488 
Decahydio-quinoline, 488, 666, 661, 692 
Decane, 696 
Decanol, 696 

Decarbonisation of 00, 614 
Decomposition of adds, 820-866 
Deoompodtion of eaten, 868-872 
Deoompodtion and oond. of hydrocarb., 

906-936 
Deoompodtions by Ni, 493 
Decydisations, 1SK3 

Dehydration, 687-727, 728-784, 786- 
816,826 

of alcohols, 138, 169, 688-727 

of alcohols with adds, 747 

of alcohol with aids., 779 

of alcohols with amines, 729 

of alcohols with ammonia, 729 

of alcohols with hydiocarb., 728 

of alcohols with hydrogen sulphide, 
743 

of alcohols with ketones, 779 

of aldehydes, 794 

of aids, with ammonia, 807 

of aids, with hydrogen sulphide, 810 

of aids, with ketones, 798 

by alumina, 713 

of amides, 811 

apparatus, 717 

of benihydrol, 720 

by beryllia, 778 



by blue oxide of tungrten, 716 
oatalyste, 638, 661, 676, 687, 702, 826 
in gas phase, 603, 694, 700-727, 731, 

801 
of glycerine, 760 
with hydrogenation, 721, 722 
by iodine, 699 
of ketones, 797 
in liquid medium, 691, 602, 696-699, 

729 
by metal oxides, 702, 763 
by mineral adds, 696, 740 
of oximes, 814 
of phenols, 786-793 
of phenols with alcohols, 789 
of phenols with amiifes, 790 
of phenols with hydrogen sulphide, 

791 
of poly-alcohols, 723, 727 
with ring formation, 727 
theory of, 169, 689 
by thoria, 716 
by titania, 767 «e seg. 
by sine diloride, 698 
Dehydroaoetic add formed, 387 
Dehydrogenation, 16, 636-686, 807--809, 

824, 910, 921 
of alcohols, 31, 660-679 
by aluminum diloride, 686 
of amines, 681, 682 
of anthracene hydrides, 642 
ai^Mtratus, 664 
by cadmium oxide, 674 
by carbon, 679 

catalysts, 636-638, 661, 676, 702, 824 
dassification, 638 
by cobalt, 666 
by copper, 663-663 
in craddng, 910 
of cydohexane compe., 641 
history of, 636 
of hydro-aromatio hydrocaib., 640- 

649 
of hydrocarbons, 630-649, 921 
of hydrocydio hydrocarbons, 640 

sfteg. 
by iron, 667 

by manganous oxide, 672 
of methyl alcohol, 676 
of naphthalene hydrides, 642 
by nickel, 664, 684 



378 



SUBJECT INDEX 



by oxides, 672-476, 686 

by palladium, 649, 669 

of piperidine, 647 

by platinum, 668 

of poly-aloohob, 680 

of aeoond. aminefl, 682 

by stamiouB oxide, 673 

of terpenes, 643 el 9eq. 

of tertiary amines, 682 

theoiy of, 168 

by various oxides, 676 

by sine, 670 
Dehydromucic add, 727 
Dekalin, 481n 
Depolymerisation, 234, 235 
Deeoxybensolne hydrogenated, 389 
Dextrine by hydrolysis, 326 

hydrolysed, 323, 326 
Diaoetonitrile, 230 

Diaoetonyl alcohol dehydrated, 698, 699 
Diaoetyl hydrogenated, 438 
Diacetyl-dihydit>morphine, 656 
Diaoetyl-morphine hydrogenated, Pd 

666, Pt 661 
Diamines by hydrogenation, 380 
Diamylene formed, 210, 211 
Diastase, 768 
Diaioacetic ester, 12 
Diaaobensene, 69, 206, 606, 607 
Diaso-oompounds decomp., 69, 606-610 

hydrogenated, 497 
Dibasic add chlorides in F. and C. qm., 

893 
Dibasic adds decomposed, 866 

esters of dec., 872-874 
Dibensal-aoetone, 798 
Dibenzoyl hydrogenated, 391 
Dibensyl hydrogenated, 462, 689 

by hydrogenation, 389, 391, 416, 648, 

690,693 
Dibenzy^acetone, 647 
Dibenzyl-amine, 428, 734 
Dibensyl-aniline, 729 
Dibenzyl-benzene, 728 
Dibensylidene-acetone hydrogenated, 

647 
Dibensyl ketone hydrogenated, 466 
Dibromethylene in F. and C. syn, 890 
Dibrom-Buccinic add, 182 
Dibutyl ketone, 844 
Dichloraoetyl chloride dec., 626 



Dichlorbenienes, 404 
Dichlorpydohexane dec., 876 
Dichlorethylene, 242 
Dicyanamide formed, 233 
Dicjranides hydrogenated, 429 
Dicydohexyl, 462, 476, 689 
Dioydohexyl-amine, 466, 469, 497, 669» 
690, 642, 739 

by hydrogenation, 386, 739 
Dicydohexyl-butanes, 462 
Dicydohexylrethanes, 462, 689 
Dicydohexy^methane, 389, 463, 660 
Dicydohexyl-pheny^methane, 463 
Dioydohexyl-propane, 466 
Dicydononane, 464 
Diethyl-allylene formed, 60, 192 
Diethyl-amine by hydrogenation, 377^ 

383, 386, 427 
Diethyl-amine. HCl catalyst, 783 
Diethyl-aniline dec. Ni, 634 

formed, 729 

hydrogenated, 468 
Diethy^bensene, 888, 930 
Diethyl-carbinol into amine, 736 
Diethyl-diphenyl formed, 241 
Diethylene compounds hydrogenated, 

647 
Diethylenic adds, 937 
Diethyl ketone formed, 838 

hydrogenated, 436, 667 
Diethyl-phenol hydrogenated, 459 
Dihalogen compounds in F. and C. 

syn*} 890 
Diheptene, 619 

Dihexahydrobenzyl-amine, 470 
Dihydrobensene, 723, 876 
Dihydrobrudne, 656 
Dihydrocampheode, 670 
Dihydrocamphorone, hydrogenated, 390 

by hydrogenation, 421 
Dihydrodnchonidine, 656 
Dihydrodtronellol by hydrogenation, 

416 
Dihydrooodeine, 672 
Dihydro-dimethyl-anthraoene, 890 
Dihydro-eugenol, 677 
Dihydro-indol, 671 
Dihydro4onones, 554 
Dihydrolimonene, 617, 691 
Dihydromorphine by hydrogenation, 
672 



SUBJECT INDEX 



379 



by oxidation, 268 
Dihydronaphtbalene, 571, 931 
Dihydiophytol, 565 
Dihydroquinine, 572 
Dihydropinene, 477, 570 
Dihydropbenanthrene, 484, 571, 592 
Dibydropborone, 547 
Dibydrosafrol, 418, 565, 590 
DibydroBtxyebnme, 555 
DibydiotetrasineB isom., 201 
Dibydroxy-acetone, 237, 246, 268 
Dibydroxy-dipbenyl-aimDe, 632 
Di-isoamyl-amine, 682, 733 
Di-iflobutyl-carbmo], 549, 567 
Di-iaobutyl ketone, 435, 567, 840 

bydrogenated, 435 
Di-isopropyl-amine, 735 
Di-isopropy^beniene from eymene, 980 
Di-isopropyl ketone f onned, 844 

bydrogenated, 435 
Diketones by debydrogenation, 663 

by F. and C. syn., 893 

bydrogenated, 391, 438-440 
Dimetbyl-aoetylene formed, 192 
Dimetbyl-acrylic acid bydrogenated, 

417 
Dimetbyl-allene formed, 192 
Dimetbyl-allyl-carbinol bydrogenated, 

587 
Dimetby^amine, 377, 430 
Dimetbyl-aniline, 468, 729, 740 

dec. Ni, 634 

oxidised, 256 
Dimetbyl-benialdebyde, 298 
Dimetbyl-butadiene, 726 
Dimetbyl-butyl-pbenol, 459 
Dimetbylrcydobexane, 197, 449, 475, 
480 

debydrogenated, Ni 641 
Dimetbyl-cydobexanols, 458, 660, 714 
Dimetbyl-oydohexene by debydration 
714 

bydrogenated, 475 
Dimetbyl-cydobexyl-amine, 467 
Dimetbyl-cydopentyl-pentanones, 436 
Dimetbyl-dietbyl-butine-diol, 548 
Dimetbyl-dipbenyl-butin^-diol, 548, 566 
Dimetbyl-dipbenyl-metbane bydrogen- 
ated, 452 
Dimetbyl-etbyl-caibinol eeterified, 757 

fonned, 210, 306 



Dimetbylene-pentane bydrogenated, 414 
Dimetbyl-beptane by bydrogenation, 

414 
Dimetbyl-bexine bydrogenated Pd, 548 
Dimetby^bexine-diol bydrogenated, 566 
Dimetbyl-indol, 490, 633 
Dimelby^isobutyl-cydobexane, 449 
Dimetbyl-ketanne isom., 196 
Dimetbyl-metbylene-cydopropane by- 

drog., 472 
Dimetbylroctane, 415, 567 
Dimetbyl-octanol, 416, 567 
Dimetbyl-octadieneol, 416 
Dimetbylroctatriene bydrogenated, 415 
Dimetbyl-octene-diol bydrogenatedi 548 
Dimetby^pentane-tbio^ 745 
Dimetby^pbenols bydrogenated, 458 
Dimetbyl-propyl-carbinol, 587 
Dimetbyl-quinoline, 491 
Dimetbyl-toluidines, 684, 740 
Dinapbtbyl debydrogenated, 685 
Dinapbtbyl-amine, 632 
Dimtrobemenes, 269n, 512 
Dimtro-compoundfl bydrogenated, 380 
Dinitro-toluenee bydrogenated, 380 
Dipentene depolymeriied, 235 

formed, 198 
Dipbenola, etben of eyn,, 904 

reduced, 370 
Dipbenyl formed, 907 

in F.and C. syn., 896 

bydrogenated, 452, 589 

by bydrogenation, 403, 406 
Dipbenyl-amine from aniline, 466 

by debydration, 642 

bydrogenated, 469, 590 

stabilixer, 13 

sulpburized, 296 

Byn. of, 901 
Dipbenyl-antbrone syn. of, 893 
Dipbenyl-benxene formed, 907 
Dipbenyl-butadione by F. and C. syn., 

893 
Dipbenylrbutanes by bydrogenation, 
520,548 

bydrogenated, 452 
Dipbenyl-butadiene, 548 
Dipbenyl-butenes bydrogenated, 415 
Dipbenyl-butine-diol bydrogenated, 548 
Dipbenyl-cydopropane, 611 
Dipbenyl-decadiene bydrogenated, 546 



380 



SUBJECT INDEX 



Diphenyl-decane, 546 
DipbenyMiaoetylene hydjogenatad, 548 
Diphenylene oxides, 787 
Diphenyl-^hanes fonned, 241, 728, 890 

by hydrogenation, 391, 415. 721, 728 

bydrogenated, 462 
Dipbenyl-ethylene fonned, 890 

bydrogenated, 415, 515 
Dipheny^methane, 369, 380, 523, 538, 

539, 590, 662, 720, 728, 806 
Dipbenyl-pentanes bydrogenated, 452 
Diphenyl-pentens bydrogenated, 415 
Dipbeny^propane fonned, 728 

by bydrogenation, 389, 415 

bydrogenated, 452 
Diphenyl-propenee bydrogenated, 415 
Dipbenyl eulpbide, 629 
Dipbenyl tbio-urea, 630 
Dipbenyl-pyraxoline dec., 612 
Dipbenyl urea, 495 
Dipbtbatid formed, 107 
Dipiperonal-acetone bydrogenated, 565 
Dipropionic nitrile, 231 
Dipropyl-amine, 427, 733 
Dipropyl-carbinol into amine, 735 
Dipropyl ketone fonned, 843 

bydrogenated, Ft 567 
Dipropylene polym., 213 
Divinyl polym., 213 

Dodecabydro-antbraoene by bydrogena- 
tion, 29, 363 
Dodecabydro-pbenantbrene debydrogen- 
ated, 642, 646 

by bydrogenation, 484 
Doremol bydrogenated, Pt 570 
Doremone bydrogenated, Pt 570 
Drying bydrogen for bydrogenaticm, 

949 
Drying oik, 266 
Dulcite, 588, 595 
Duodeoene polym., 210 
Duratol, 967 
Diuene bydrogenated, Pt 569 

Egg ledtbine bydrogenated, Pd 555 
Elaldio acid formed, 82, 184 

esters of, 937 

bydrogenated, 422 

into ketone, 843 
Electric beating, 349 
Electrolytic dissociation, 175 



EUmination of ammonia, 631-633 

of aniline, 634 

of carbon, 613 

of carbon monoxide, 618-625 

of balogens, 605 

of bydrogen sulpbide, 626-620 

of nitrogen, 606-610 
Ellis's apparatus, 962 
Emulaine, 18, 327, 329 
Ensymes, I8O0 
Eqidlibrium in aloobolysis, 340n 

sbifted,180f 
Erdmann's apparatus, 958 
Erudc acid, 184 

esters of, 937 
Ery tbrol formed, 83 
E^terification, 747-778 

by acid anbydrides, 761 

of bensoic add, 758 

by beryllia, 778 

catidytic, 17, 747-778 

of formic add, 773 

in gas pbase, 762-777 

of glycerine, 760 

limits, 21, 760-752, 767-770 

in liquid pbase, 748-761 

mass law, 770 

iates,775 

tbeory of, 177, 762, 763 

by titania, 767 

vdocity, 747, 774, 777 
Eaters from aldebydes, 226-228 

witb ammonia, 871 

as catalysts, 104 

condensed, 803 

decomposed, 180n, 858-874 

fonned, 75, 170, 175, 226-228 

bydrogenated, 417 

bydrolysed, 83, 170, 313-^16, 319, 
321, 337 

saponified, 175, 305, 337 
Etbane, 423, 518, 526, 627, 546, 558, 
601, 606, 620, 631, 665, 709 

from acetylene, 26, 914 

decomp by beat, 911 

deoomp. by Mg, 920 

from etbylene, 912 

formed, 409 

by bydrogenation, 26, 342, 377. 412, 
413, 912, 914 
Etber oond. witb bensene, 817 



BITBJBCT INDEX 



381 



deoomp., 180m, 888 

formed, 160, 190g, 690, 764, 872 

in Gri^iard reagent, 6 

oxidised, 264 

prooetB, 160, 601 
Ethers, cataljrsts, 104 

decomp., 180m, 821, 838, 404 

formed, 160, 600, 764, 872 

hydrogenated, 418 
EthoxyH^dohexane, 464 
Ethyl acetate from aldehyde, 228 

catalyst, 304, 605 

deoomp., ISQf, 1801, ISOti, 858, 861, 
861n, 871 

formed, 228, 407, 740 

hydrolyied, 313, 316, 810 

neg. cat., 11, 303 
Ethyl acetoaoetate hydrogenated, 387 
Ethyl-aoetylene, 102 
Ethyl alcohol, 680, 742 

into aoetal, 780, 783 

into acetol, 783 

into amines, 732 

catalytic solvent, 38 

decomposed, 650, 670 

dehydrated, 688, 601, 604, 606, 700, 
702, 700, 713, 716-710 

dehydrogenated, 538, 656, 667, CdO 
674, MnO 672, Ni 664, Pt 668, 
SnO 673, Zn 670 

esterified, 750, 770, 771, 773 

hydrogenation agent, 538 

oxidised, 150, 1806, 240, 264, 257, 260, 
268 
Ethyl adipate dec., 874 
Ethyl-amine cat. prep., 732 

con. agent, 804 

dec. by Ni, 631 

hydrochloride catalyst, 783 

by hydrogenation, 377, 382, 386, 510 

oxidised, 256, 268 
Ethyl-aniline dec., 634 

hydrogenated, 468 

prep., 720 
Ethyl-bensene, 451, 516, 520, 538, 530, 
546, 548, 560, 641, 657, 728 

decomp., 888, 030 

formed, 362, 360, 380, 415, 817, 888, 
800 

hydrogenated, 362, 448, 534 

by hydrogenation, 362, 360, 380, 415 



Ethyl bensoate, 744n, 740, 754, 755, 766 

dec., 858, 864, 871 

hydrolysed, 316, 310 
Ethyl bromide formed, 104 
Ethyl bromaoetate reduced, 407 
Ethyl-tert-butyl-bensene, 380 
Ethyl-tert-butyl ether, 601 
Ethyl butyrate dec., 858 

by hydrogenation, 387 
Ethyl caproate dec., 861, 862 
Ethyl carbylamine hydrogenated, 430 
Ethyl chloraoetate red., 407 
Ethyl chloride chlorinated, 282 

by F. and C. reaction, 888 
Ethyl dnnamate hydrogenated, 601 
Ethyl cyanide catalyst, 106, 606 

hydrogenated, 427 
EthylH^olohexane dehydrogenated, Ni 
641 

by hydrogenation, 362, 448, 451, 452, 
455, 516, 520, 568, 560 
Ethyl-cydopropane, 103 
Ethyl-diphenyl formed, 241 
Ethylene, 423, 527, 548, 620, 626, 631, 
634, 650, 670, 686, 680, 601, 606, 
700, 708, 700, 713, 716, 726, 732, 
864,871 

cond. with bensene, 241 

cond. by sulphuric acid, 150 

dec., 637, 012, 020, Co 012, Fe 012, 
Mg 020, Ni 413, Pt 012 

formed, 78, I8O9, 873, 014 

hydrogenated, Co 500, Cu 516, Ni 413, 
601, Pd 546, Pt 526, 558 

manufacture, 180A, 680n, 717n 

oxidised, 1806 

polymerised, 211 

preparation, 606n 
Ethylene bonds hydrogenated, 030 
Ethylene compounds hydrated, 306 

hydrogenated, 412-422, 587, Co 500, 
Cu 515, 504, Fe 506, Ni 601, Pd 546, 
577, Pt 526, 558, 565 
Ethylene chloride in F. and C. syn., 800 

oyanide hydrogenated, 420 
Ethylene hydrocarbons formed, 48, 86, 
681, 682 

in F. and C. oyn., 00, 241 

hydrogenated, Co 500, Cu 615, Fe 506 

polymerised, 210 
Ethjdene oxides hydrogenated, 443 



382 



SUBJEC3T INDEX 



iflomerised, 200 
Ethylenie acids, 937 
Ethylenic chlorides, 243 
Ethyl ether, 694, 089, 713 

oat, 605 

formed, 873 

hydrogenated, 494 

prepared, 691 
Ethyl formate, 773, 866 

dec., 866 

hydrolyied, 316 
Ethyl glutarate dec., 874 
Ethyl hexahydrobensoate, 471, 476 
Etl^lidene chloride in F. and C. oyn., 890 
Ethyl iodide oat., 299 

in Grignard reaction, 302 

in syn., 605, 901 
Ethyl-isoamyl-amine, 738 
Ethyl-jsoamyl ether, 691 
Ethyl-iaobutyl ether, 691 
Ethyl isobutyrate, 316, 319 
Ethyl isovalerate, 417 
Ethyl malonate dec., 783 
Ethyl mercaptan, 626, 744 
Ethyl-methyl-hexene hydroisenated, 414 
Ethyl-naphthalenes by hydrogenation, 

390 
Ethyl naphthoates to nitriles, 871 
Ethyl nitrate cond., 819 
Ethyl nitrite as cat., 104, 207 

hydrogenated, 382 
Ethyl oleate hydrogenated, 565 
Ethyl ortho-formate, 783 
Ethyl oxalate as cat., 104 

dec., 873 
Ethyl phenyl-aoetate dec., 871 
Ethyl-phenyl carbinol, 728 
Ethyl-phenyl ether, 789 
Ethyl propionate dec., 858 
Ethyl-propyl ether, 691 
Ethyl-pyridines gyn., 901 
Ethyl-pyrrol, 742 
Ethyl stearate dec., 858 

by hydrogenation, 565 
Ethyl succinate dec., 873, 874 
Ethyl sulphide, 626 
Ethyl terephthalate, 590 
Ethyl tetrikhydrobenioate, 476 
Ethyl toluate, 590 
Ethyl-toluidines, 489 
Ethyl-trimethylene hydrogenated, 472 



by hydrogenation, 577 
Ethyl valerate dec., 864 

sapon., 316, 319 
Ethyl vanilline hydrogenated, 568 
Eucalyptol dehydrogenated, 645 
Eucarvone hydrogenated, 552 
Eudesmene hydrogenated, 570 
Eugenol hydrogenated, Ni 590, 603, Pd 
577, Pt 565, 569 

isom., 191 
Eugenol methyl ether hydrogenated, 590 

F^co, 967n 

Famesol hydrogenated, 570 

Fats alcoholiied, 341 

hydrogenated, 542, 937-969 

saponified, 314, 317 
Fatty adds, effect on Ni, 948 

by hydroL, 314, 315, 318 
Fenchane, 611, 722 
Fenchone, 611 

Fenchyl aJcohol dehydrated, 722 
Ferments, soluble, 18 
Ferric chloride acetal cat., 781, 783 

catalyst, 687, 843, 849, 878 

chlorination cat., 285, 285fi 

cond. cat., 902 

in F. and C. oyn., 899, 900 
Feme oxide defaydiogenation cat., 677f 
686 

ketone cat., 843, 849 

mixed cat., 702 
Ferric sulphate cat., 725 
Ferrous carbonate chlorination cat., 285 
Ferrous chloride cat., 876, 954 

in F. and C. qm., 899 
Ferrous oxide cat., I8Q7, 827 

ketone cat., 843, 849 
Ferulene hydrogenated, 570 
Fibrine cat., 110 
Fish oils, effect on cat., 947 

hydrogenated, 939, 967n 
Fittig syn., 11, 
Flake white, 967n 
Fluorides cats., 841 
Fluorene by dehydrogenation, 642 

in F. and C. syn., 896 

hydrogenated, 454 
Formaldehyde, 73, 236, 562, 656, 664, 
672, 674, 676, 678, 821, 825, 826, 
851, 870 



SUBJECT INDEX 



383 



catalyst, 269n 

dec., Cu 621, FeiO^ 677, Pd 623 

into ester, 225, 228 

formed, 866, 871 

hydrogenated, 432 

by oxidation, 249, 252-254, 256 

with phenols, 792 

preparation, 249, 252-254 

into sugars, 221 
Formates, 851 

Formic acid, 64, 621, 839, 851, 852, 855, 
866 

decomp., 99, 143, 172, ISOg, 624, 820- 
828 

esterified, 773 

hydrogenating agent, 537, 539, 604 

by oxidation, 249 

oxidised, 246 

syn. of, 574 

toxic to Ft black, 117 
Formic esters dec., 624, 866-870 
Form of metals, 41, 53-^5, 76-^ 
Formyl chloride, 298 
Fouling of catalysts, 118-120, 122, 932 
Friedel and Crafts synthesis, 33, 87-89, 
157, 173, 174, 241, 241n, 297, 298, 
883-900 

catalysts for, 899, 900 

catalytic nature of, 898 

complications, 885 

cyclic compounds, 896-898 

with diphenyl, 889 

with ethylene hydrocarb., 241 

isomerizations in, 888 

of ketones, 891-894 

mechanism of, 898 

method of operating, 884, 892 

with naphthalene, 889 

results of, 889 

reversed, 887 
Fructose, 186, 324 
Fumaric acid esterified, 756 

esters from maleic, 182 

hydrogenated, Pd 546 

isom., 182 

from maid c, 182 
Furfural cond., 686 

decom., Ni 620 

formed, 727 

hydrogenated, 434 

oxidised, 268 



Fuif urane, 620 

Furfurane-dicarbonic add, 727 
Furfurane rings, 727 
Furf urolne formed, 220 
Furfuryl alcohol, 371, 434 
Furfuryl-ethyl carbinol hydrogenated, 
487 

Galdic add formed, 184 
Galactobiose, 18 
Galactose, 18, 186, 188 

hydrogenated, Ni 588, Pd 595 

by oxidation, 268 
GaUdan petroleum, 927 
Galtose formed, 186 
Gases condensed by metal powders, 135 

in porous bodies, 131, 132, 134 
Gases from cracking, 909 
Gasoline by cracking, 906, 932-036 
Geometrical isomers, 182 
Geraniol dehydrogenated, 658 

hydrogenated, Ni 416, 601, Pd 595, 
Pt565 
Glass powder as oat., 811, 827, 828 
Gluconic add, 187 
Glucose hydrogenated, Ni 588, Pd 595 

by hydrolysis, 324-329 

isomerised, 186 

multirotation of, 188 
Glucosides dec., 18, 175 

hydrolysed, 305, 327-^0 

eyn., 15, 18, 793 
Glutaryl chloride in F. and C. syn., 893 
Glyceric aldehyde cond., 237 

formed, 236, 246, 268, 680 

by oxidation, 268 
Glyoerides saturated, 939 
Glycerine aoetylated, 89 

by alcoholysis, 340, 341 

dec. to formic acid, 855 

dehydrated, 725 

dehydrogenated, 680 

esterified, 757, 760, 761 

esters of, 340, 937 

by hydrolysis, 314, 318 

oxidised, 246, 249 
Glycol dehydrated, 724 

oxidised, 249, 268 
Glycolic add esterified, 756 
Glycolic aldehyde by oxid., 249, 268 
Glyoxal by oxid., 249, 268 



384 



SUBJECT INDEX 



Gold, abeorptioD of 0| by, 187 

catalyst, 66 

colloid, 70, 72 

dehydiogenation cat., 687 

oxidation cat., 262, 264 
Gold chloride, chlorination cat., 288 
Goose fat, 038 
Giapbite catalyst, 702, 717, 911 

fonnatton, 180a 
Grease cat. poison, I8O0 
Greenwich gas works, 373 
Grignard reaction, 44, 104, 800-802 
Guaiaool hydrogenated, Ni 680 
Gulose, 186 
Gum arable, 646, 661 
Gunpowder dec., 8 

Halides,800 

Halogenated alcohols dec., 876 
Halogens eliminated by hydrogenation, 
403-407, 646, 606 

toxic to catalysto, 112-114 
Hardened oils as foods, 067n, 060 

trade names of, 067 
Hardening of fats, 677 

of oils, 037-060 
Heavy hydrocarbons cracked, 032 

by cracking, 006, 036 
Heavy oils by cracldng, 006, 036 
Helidne hydrolyied, 328 
Helleborine, 330 
Heptachlorpropane decom., 870, 367 

fonned, 242, 626, 003 
Heptachlortoluene formed, 287 
Hepta-isobutanal formed, 224 
Heptaldehyde oond., 706 

crotonised, 706 

hydrogenated, 660 

prepared, 863 
Heptaldoxime hydrogenated, 383 
Heptamethylene ring hydrogenated, 470 
Heptane by cracking, 036 

by hydrogenfttion, 610 
Heptane-thiol, 746 
Heptane hydrated, 306, 610 
Heptine hydrogenated, 426, 610 
Heptoio acid into aldehyde, 863 

into ketone, 846 
Heptoic aldehyde, 664 
Heptyl alcohol dehydrogenated, 664 

by hydrogenation, 660 



Heptyl-amine by hydrogenation, 888 
Heterogeneous gystems, 7, 84 
Hexachlorbenxene, 284 
Hexachlorethane, 280 
Hexachlorpropane, 242 
Hexachlortoluene, 287 
Hexadienal, 706, 801 
Hexahydro-acetophenone, 476 
Hexahydro-anisol, 680 
Hexahydro-anthrone hydrogenated, 800 
Hexahydro-bensoic add, 471, 476, 651, 
660, 660, 600 

dehydrogenated, 640 

esters of, 471, 640 
Hexahydro-beniyl-amine, 470 
Hexahydro-bensyl-aniline, 660 
Hexahydro-carvacrol, 460 
Hexahydro-cinchonine, 661 
Hexahydro-c3rmene, 466, 478 
Hexahydro-durene hydrogenated, 660 

llflKIHIjmVguaMKJUI, vOV 

Hexahydro-indoline, 486 
Hexahydro4iaphthalid, 663 
Hexahydro-phenanthrene, 484 

dehydrogenated, 642 
Hexahydro-phen^acetic add, 476 
Hexahydro-phthalic add, 663, 500 
Hexahydro-phthalid, 663 
Hexahydro-phthalimide, 660 
Hexahydro-terephthalic add, 648 
Hexahydro-toluene, 581 
Hexahydro-toluic adds, 471, 663 
Hexahydroxy-anthraquinone, 274 
Hexahydroxy-beniene hydrogenated, 578 
Hexa-isobutanal formed, 224 
Hexamethyl-bensene decom., 887 

formed, 212, 601 
Hexamethylene hydrocarbons dehydro- 
genated, 640 

hydrogenated, 475 
Hexamethylene-tetramine cond., 702 

hydrogei^tted, 406 
Hexane from acetylene, 211 

by cracking, 036 

decom., 020 

formed, 664, 665 

by hydrogenation, 414 

as solvent, 38 
Hexaphenyl-cyclohexane, 880, 016 
Hexene hydrated, 306 

hydrogenated, 414, 515 



SUBJECT INDEX 



885 



Hexites, 606 

Hexo0e from HCHOi !221 

Bbxyl alooholi 801 

Hexyl-beniene hydrogenated, 609 

Hexyl cyanidei 814 

High preesure in oatalysiB, 641 

Histoiy of catalysiB, 4 

HofmAim's leaetion, 901 

Hog lard, 93^ 

HomogeneoUB cataljBiB, 6, 144 

Hydration, 306-312, 306-^39 

of acetylene oompe., 308 

of ethylene oomps., 306, 307 

in gas phaae, 337-339 

of imides, 311 

in liquid medium, 819^331 

mechanism of, 306 

of nitriles, 311 
Hydrasine compoonds deoom., 611 
^ydralobenIene, 202, 631, 664 
Hydraio compounds hydrogenated, 600 ' 
Hydrazones decom., 611 
^ydrindene, hydrogenated, 464 
Hydrindone cond., 799 
Hydro-aromatic hydrocarbons, 424, 444 

dehydrogenated, 640-^649 
Hydrobensamide, 194 
Hydrobromic add dim., 901 
Hydrocarbons from acetylene, 926 

from adds, 829-836, 839 

from alcohol + aldehyde, 784 

condensed, 241, 905-036 

deoom., 87, 493, 906-036 

decom. in Hs, 924 

dehydrogenated, 639-649 

hydrogenated, 413, 444-464, 472 et 
Mg. 481-485, 493, 600-W2, 606» 
615-618, 626, 627, 634, 666, 666, 
569, 570, 577, 601 

formed, 695-727, 784-816, 829-836, 
839,925 

oxidised, 264, 259 

polym.,84 
Hydrocarvols, 476 
Hydrochloric add cat. acetals, 782 

cond. agt., 730, 782, 792, 799, 803-805 

dehydration cat., 687, 796 

in esterif ., 748-760, 764-767 

in hydration, 307 

toxic to cats., 116 
Hydrodnnamic esters hydrogenated, 471 



Hydrm^yanio add hydrogenated, 842, 

628 
by hydroljrsis, 329 
polym., 230 
stabilised, 11 
toxic to cats., 116 
Hydrooydic hydrocarb. dec., 921 
Hydrogen abs. by Co, 136, by Pd 165, by 

Ptl36 
dim. from hydrocarb., 906 
generator, 346 
for hydrogenation, 963 
influence in dec. hydroc, 924 
from iron, 964 
manufacture, 968, 964 
ooduded by Co, 136, by Pd 166, by 

Pt 136, 166 
purification of, 346 
rate of production from Fe, 964 
from water gas, 963 
Hydrogenation, 16, 66, 111, 116, 121, 

138, 166, 342-407, 40^^97, 498- 

540, 541-^583, 663fi. 684-604, 721, 

923, 931, 932, 937-969 
of acetylene, 501, 506 
of acetylene comps., 423 H Mg., 618, 

627, 566, 577 
of add chlorides, 676 
of adds, 422, 471 
of acridine, 491 
by alcohol vapors, 637, 638 
of alcohols, 369, 416, 465 
of aldehydes, 388, 419, 432, 433, 603, 

522, 532, 567, 588, 602 
of aliphatic aldehydes, 432, 632 
of aliphatic amides, 386 
of aliphatic ketones, 632 
of aliphatic nitriles, 427 
of aliphatic nitro comps., 877 
of alkaloids, 666 
of amides, 386 
of amines, 466, 496 
of anhydrides, 392 
of anthracene nudeus, 483 
apparatus, 345-357, 543, 684-^»6, 697 

et Mg., 957-964 
of aromatic adds, 471 
of aromat. ales., 369, 466 
of aromat. aids., 388, 433 
of aromat. amines, 466 
of aromat. diketones, 391 



386 



SUBJECT INDEX 



ai aromat. halofon oomps., 403 

oi aiomat. hydrooub. 466 H Mg., 502 

of aromat. ketonM, 389, 466 

of aromat. mtrfles, 428 

of aiomat. nitro oomps., 378 

oi aromat. nucleus, 444 e( 9eq,, 634, 

660,689 
ci benieue and homologs, 466 el Mg., 

602 
oi carbaiol, 490 
oi carbon 625 

of carbonates to formates, 674 
of carbon dioxide, 395, 604, 608 
of carbon disulpbide, 372, 492 
of carbon monoxide, 393 
by carbon monoxide and hydrogen, 

537 
by cobalt, 499^604 
by colloidal Pd, 646-^566 
by colloidal Pt, 666 
of complex rings, 671 
by copper, 607, 523, 694 
of cydic comps., 678 
with dehydration, 721, 722 
of diaso comps., 497 
of di<^yanides, ^29 
of diketones, 438 
of esters, 417 
of ethers, 418, 494 
of ethyl acetoacetate, 387 
of ethylene comps., 600, 606, 616, 526, 

666, 677, 601 
of ethylene hydrocarb., 600, 606, 616 
of ethylene oxides, 443 
by formic add, 637, 539 
of furfuryl alcohol, 371 
furnace for, 347, 348 
ingaagystem, 360-407 
of halogen comps., 403 et 9eq, 
of heptamethylene ring, 479 
of hexamethylene ring, 476 
history of, 342-^44, 542, 939 
of hydrocarbons, 413, 493, 499 «< 9eq. 
hydrocyanic add, 628 
of indol, 497 
by iron, 606, 506, 693 
of iBOcyanides, 431 
of keto-adds, 437 
of ketones, 389 et Mg., 420, 436 el seg. 

441, 455, 503, 522, 532, 567, 588, 

602 



of liquid fata, 937-M9 

in liquids, 360-362, 641 el eeg., 584 s( 
seg., 690-603 ^ 

in manuf . oi iXL gas, 397 el deq. 

methods, 343 eleeg., 544, 662, 673, 68^ 
696, 597, 599, 604 

of naphthalene nucleus, 481, 931 

by nascent hydrogen, 537 

d nitfiles, 437, 428, 621 

of nitro comps., 377, 378» 609, 529, 
564, 676, 600 

oi nitrous esters, 613 

oi nitrous oxide, 368 

of oetomethylene ring, 480 

of oxides of carbon, 604 

by oxides of metals, 598, 943 

of oxides of N, 374 

of oximes, 283, 514 

by palladium, 636, 544-^555, 673-678 

l^ palladium blade, 573-578 

of pentamethylene ring, 474 

of phenanthrene nucleus, 484 

of phenol ethers, 464, 494 

of phenols, 370, 456 

of phenyl isocyanate, 495 

by platinum, 524-^»36, 656^71 

by platinum black, 562-^572 

of polycydic hydrocarbons, 452 

of pdymethylene rings, 635 

of polyphenols, 370, 460 

products, 355, 356, 965 

of pyridine, 486 

of pyromudc aid., 434 

of pyrrol, 486 

of quinoline, 488 

of quinones, 442 

removes odors, 939 

results of, 355, 356, 965 

of soUds, 353 

temperatures for, 599 

of terpenes, 477, 570, 691 

of tetramethylene ring, 473 

theory of, 167, 365 

of trimethylene ring, 472 

by various metals, 580, 596 

of various rings, 472 et eeg., 571, 692, 
603 
Hydrogen halides dim., 875-903 
Hydrogen ions in hydrol, 82, 313, 324 
Hydrogen peroxide decom., 2, 32, 38, 83, 
160, 180a 



SUBJECT INDEX 



387 



with ehromio acid, 147 

oxidising agt., 268 

with pennanganate, 148 

stabilised, II, 13 
^yd^ogen persulphides, 83 
Hydrogen selenide deoom., 8 
Hydrogen sulphide, 686, 743, 791, 810, 
924,947 

with alcohols, 743 

with aldehydes, 810 

elim., 626-629 

isom. agt., 182 

toxic to cats., 180o, 598, 947 
Hydroiodio add cat., 82, 183 

deoom. limit, 15, 20 

formation, 342 

isom. cat., 182 
Hydroledthin, 555 
Hydrolysis, 82, 17&-178, 305, 31^-^6 

of acetals, 322 

by adds, 313 

of amides, 331 

by bases, 318 

of carbon distdphide, 339 

of esters, 313-319, 337 

of ethers, 321, 338 

in gas system, 337-339 

of gluooddes, 327 

of halogen oomps., 320 

of polysaccharides, 323 
Hydropivalic acid esterif., 227 
Hydroquinine, 604 
Hydroquinone by hydrogenation, 442 

reduced, 370, 461, 589 
Hydroxy-adds esterif., 756 
Hydroxy-anthraquinones by oxidation, 

274 
Hydroxy-benzoic add hydrogenated, 

569 
Hydroxy-butyric aldehyde formed, 307 
HydroxyH^dohexanes dehydrated, 642 
Hydroxy-esters dehydrogenated, 663 
Hydroxy-isoheptoic add, 663 
Hydroxylamine by hydro!., 332 
Hydroxyl group dim., 465 

introduced, 269 
Hydroxy-methylene comps. hydrogen- 
ated, 550 
Hydroxy-Stearic add formed, 306 

toxic to cats., 115 
Hypochlorites as oxidising agents, 270 



Hypogaeic add, 184 
esters of, 937 

Dliiminating gas by hydrogenation, 397* 
402 

freed from GSt, 372 

manufacture, 397-402 

purification, 339, 372 
Imbibition of liquids by porous sub., 133 
Imides, 305, 312 
Indene polym., 217 
Indoee, 186 

Indigo hydrogenated, 165, 603 
Indigotine hydrogenated, 603 
Indigo white, 165, 603 
Indol, 684 

hydrogenated, 497, 571 
Indols cond., 803 

formed, 89, 91, 633 
Induced catalysis, 149 

oxidations, 244 
Influence of solvents, 38^-40 
Infra-red radiation as cat., 18Q; 
Infusorial earth as carrier, 126^ 587ny 

598, 941 
Inodte, 578 

Intermediate oomps. in cat., 151-158, 
163-173, 179, 180, 752, 763, 85^ 
864, 866, 872, 878, 898, 916 

in esterif., 752, 763 

in F. and C. syn., 898 

in oxidation, 258, 541, 677 
Inverdon of reactions, 14 

of sugar, 32, 324 
Iodides cats., 84 
lodination, 294 
Iodine absorbed, 938 

bromination cat., 291 

catalyst, 6, 33, 43, 156, 278, 299, 632 

chlorination cat., 156, 278n, 287 
Iodine 

dehydration cat., 699, 729, 790 

dim., 406, 605 

isom. cat., 182 

sulphonation cat., 296, 815, 815n 

toxic to cats., 116, 359 
Iodine numbers, 938, 955 

of hardened oils, 967, 967ii 

in hydrogenation, 966 
Iodine trichloride catalyst, 44, 85, 150 

chlorination cat., 85, 278 



888 



SUBJECT INDEX 



lodobeoaene reduoed, 406 

mom., 904 
lononea fonned, 198 

hydrogenated, 654, 560 
Ions in hydrolysifl, 305 
Iridium black, 582 

catalyst, 64 

colloidal oxid. oat., 251 
Iran, bTomination oat., 298 

catalyst, 167, 180r^l80tt, 820, 844, 
506, 606, 640, 683 

catalyst, prep, of, 58 

chlorination oat., 278vi, 285, 285fi 

cracking cat, 906, 910, 911, 932 

dec. CiHi, 913, 915, 920, 928 

dec. aloohob, 667 

dec. ar^mat. hydrocarb., 921 

deo. CO, 615 

dec. ethylene, 912 

dec. pinene, 922 

dehydrogenation cat., 637, 651, 662, 
667 

in drying oils, 266 

harmful in hydrogenation, 115 

hydrogenation cat., 344, 506, 506, 593, 
946 

in hydrolyms of benialchloride, 320 

influence on Pd, 946 

method for prep, of hydrogen, 953, 
954 
Iron bensoate, 320 
Iron borate cat., 265 
Iron bromide, brominatton cat., 240, 293 
Iron chloride, bromination cat., 293 

chlorination cat., 283 

cracking cat., 936 

in F. and C. syn., 88 

halogenation cat., 88 

hydration cat., 310 

polym. oat., 216 

prep, acetals, 88 
Iron compounds cats., 269fi 
Iron hydroxide oxid. cat., 150 
Iron oxides cat., 6, 75, 100, 260, 285, 310, 
320 

dehydration cat., 702 

hydration cat., 310 

ketone cat., 843, 849 

oxidation cat., 257-269 

prep., 77 
Iron powder cat., 320 



Iron retorts in onddng, 934 

Iron salts oxid. cat., 268, 271, 277, 320 

reduced, Pd 165 
Iron scale cat., 285 

Iron sesquioxide chlorination cat., 285 
Iron sulphate chlorination cat., 285 

oxidation cat., 272, 275 
Iron sulphide chlorination cat., 284 
Isoamyl acetate dec., 871 
Isoamyl alcohol into amines, 783, 740, 
741 

dehydrated, 601, 696, 713, 715, 717, 
719 

dehydrogenated, 656, 664, 672 

esterified, 771, 778 

oxidised, 264, 268 
Isoamyl amine from alcohol, 733 

catalyst, 836 

dehydrogenated, 681 

by hydrogenation, 382 
Isoamyl bensoate, 766 
Isoamyl-carbinol hydrogenated, 570 
Isoamyl cyanide hydrogenated, 427 
Isoamyl ether, 691 
Isoamyl formate, 773 
Isoamyl hexahydrobensoate, 471 
Isoamyl malonate dec., 873 
Isoamyl mercaptan, 626, 744, 746 
Isoamyl nitrite hydrogenated, 382 
Isoamyl oxalate dec., 873 
Isoamyl-phenyl ether, 789 
Isoamyl-piperidine, 741 
Isoamyl succinate dec., 873 
Isoamyl sulphide, 626 
Isobutane, 472 

Isobutyl acetate dec., 861, 862 
Isobutyl alcohol into aoetal, 780 

from aldehyde, 226 

dehydrated, 691, 696, 700, 713, 715- 
717 

dehydrogenated, 666, 670 

esterified, 771, 776 

oxidised, 249, 264, 268 
Isobutyl-amine by hydrogenation, 382 
Isobutyl bensoate, 766 
Isobutyl bromide isom., 200 
Isobutyl chloride dec, 878, 881 

in F. and C. eyn., 900 
Isobutyl cyanide, 681, 682 
Isobutylene formed, 142, 713, 878 

hydrated, 306 



SUBJECJT INDEX 



389 



Isobutyl etheij 691 
Isobutyl hexahydrobenxoatei 471 
Iflobutyl-isoamyl-aminei 738 
Iflobutyl isobutyrate from aid., 226 
Isobutyl malonate dec., 873 
Iflobutyl meroaptan, 744 
Isobutyl nitrite hydrogenatedi 382 
Isobutyl oxalate dec., 873 
Iflobutyl succinate dec., 873 
Iflobutyric add from aid., 226 

dec., 839 

esterif., 770, 771, 775, 776 

into ketone, 840, 842-845 
Isobutyric aldehyde from ale, 670 

cond., 808 

crotonixed, 795 

into ester, 226 

hydrogenated, 432, 588, 593 

by oxidation, 249 

phenylhydrazone dec., 635 

polymerized, 224 
Isobutyryl chloride, 813 
Isocamphane, 591, 722 
Isocrotonic add hydrogenated, Pd 546 
Isocyanates from diazo, 610 

hydrogenated, 431 
Isocyanides hydrogenated, 431 
Isocyanic esters hydrol., 334 
Isoduldte by hydrol., 328 
Isoeugenol formed, 191 

hydrogenated, Ni 590 

oxidifled,249 
Isoheptoic aldehyde, 635 
iBomerisationfl, 181-208 
of alkyl haUdes, 876 

in F. and C. syn., 888 
Iso-oleic add hydrated, 306 
Iso-oximes formed, 205 
Isopentane, 681 

by hydrogenation, 414, 420, 472 
Isopentene isom., 190 
Isoprene formed, 235, 723, 802, 909 

polym., 50, 106, 213, 214 
iBopropyl-aoetylene, 192 
Isopropyl alcohol, 439, 503, 567, 588, 
593, 594, 784 

into amine, 735 

dec. by C, 679 

dehydrated, 700, 716, 719 

dehydrogenated, 659, 665, 668 

esterif., 757, 766, 775 



from gases, 306n 

by hydrogenation, 391 

oxidised, 254n 

preparation, 435 
Isopropyl amine from ale, 735 

by hydrogenation, 382 
Isbpropyl-benzene hydrogenated, 448 
Isopropyl bensoate dec., 871 

formed, 766 
Isopropyl bromide by isom., 93, 199 
Isopropyl chloride by isom., 199 
Isopropyl-f^dohexane, 449, 452 
Isopropyl-oydohexyl-amine, 739 
Isopropyl-f^dopentanone, 546 
Isopropyl-ethylene, 713 
Isopropyl-guaiacol, 565 
Isopropyl iodide, 605 
Isopropyl nitrite hydrog., 382 
Isopropylidene-cydopentanone hydrog., 

546 
Isosafrol hydrogenated, 418, 565, 590. 

601 
Isoeulphocyanic esters hydro!., 334 
Isothujone formed, 198 

hydrogenated, 552 
Isovaleraldoxime, 814 
Isovaleric add into aid., 853 

dec, 839 

esterif., 771 

into ketone, 842^844 
iBovaleric aldehyde cond., 808 

formed, 664 

hydrogenated, 432, 588 

by oxidation, 268 

phenylhydraaone dec., 635 
Isovaleric anhydride into ketone, 857 
Isovaleric esters dec., 871 
Isovalerone, 420 
iBovaleronitrile, 814 
Isovaleiyl chloride, 813 
Isozingiberene hydrogenated, 570 
Itaconic add formed, 183 

hydrogenated, 558 

isom., 183 

Jena glass cat., 827 

Kaolin carrier for Ni, 941 
dehydration cat., 99, 717, 723, 726, 

802 
oxidation oat., 267 



390 



SUBJECT INDEX 



EajBer's apparatus, 963 
KetimineB f onned, 809 
Eeto4cid8 esterif., 756 

hydiogenated, 437 

syn. of, 902 
Keto-aloohols dehydrogenated, 663 
Keto osten, 663 

Keto-hydrofuifuranes fonnedi 196 
Keto-uoheptoic esten, 663 
Ketones from aloohds, 650, 659 

into alcohols, 549 

aUcydie hydrogenated, 436 

aliphatic hydrogenated, 435 

aromatic hydrogenated, 441, 455 

condensed, 81, 238, 794-801, 803-810 

condensed in gas phase, 801 

crotonised, 794h800 

orotonixed in gas phase, 801 

decom., Ni 620, Pt 532 

dehydrated, 794-800, 802 

from esters, 860, 861 

formed, 31, 75, 206, 332, 701, 723, 764, 
829, 830, 837-^1, 857, 858, 865, 
891-894 

formed in liq. phase, 847 

by hydration, 305, 308 

hydrogenated, 420, 435, 436, 441, 455, 
Co 503, Cu 522, Fe 506, 593, Ni 588, 
602, Pd 549, Pt 532, 567, 568 

from oximes, 332 

polym., 229 

from second, ales., 659 

Byn. by F. and C, 891-894 
Ketoximes dehydrated, 814 

hydrogenated, 383, 385, 514 
Kieselguhr, carrier, 942 
Eream Krisp^ 967n 



toxic to cats., 115 
Lead chamber process, 32, 158 
Lead chloride cat., 876, 

not cat. 283 
Lead hydroxide, isom. cat., 186 
Lead nitrate, oxidation cat., 277 

reduced with Pt, 166 
Lead oxide cat., 676 
Lead soaps toxic to cats., 115 
Life of catalysts, 111, 708, 947 
Ligrolne as solvent in F. and C. syn., 

892,897 
Lime catalyst, 540, 827 

decom. metiiane, 911 

dehydration cat., 795, 797 

ketone cat., 840, 849 
Limits of esterification, 750, 751, 767- 
770 

change with temperature, 76^770 
Limits of reactions, 22, 313 
Limonene dehydrogenated, 644 

formed, 198 

hydrogenated, Cu 517, Ni 477, 591, 
Pt570 
Linalool hydrogenated, Ni 416, 601, 

Pt565 
Linolelc acid constituent of fats, 937 

hydrogen req. for sat., 955 

hydrogenated, Pd 558 
Linolelc esters, 937 
Linolenic esters, 937 
Linseed oil alcoholiied, 341 

hardened, 966 

iodine number, 938 
Liquid fats hydrogenated, 937-969 
Lithium carbonate ketone cat., 846 
Lyxonic add, 187 



Lactones by hydrogenation, 392 

Lactose, 323 

Laevulinic add esterif., 756 

hydrogenated, 437 
Laevulose formed, 221, 236, 237 

hydrogenated, Ni 588, Pd 595 

multirotation, 188 
Lampblack cat., 811 
Lard, 938 

Lard oil hardened, 966 
Laurie add into ketone, 843, 850 
Lead in diying oils, 266 

influence on, Pd 946 



Magnesia carrier, 127 

catalyst, 540, 702, 828, 901, 906, 920 
Magnedum carrier, Pd 946 

cat, 51, 901 

in cracking, 906 

dec. CtHi, 920 

powder cat., 901 
Magnedum compounds cats., 269n 
Magnedum sulphate dehydration cat., 

101 
Maldc add cat., 196 

hydrogenated, 558 

isomer., 182 



SUBJECT INDEX 



391 



by oxiclAtion, 260n, 276 

oxidifled, 268 

toxic to oats., 115 
Malic acid eBteiif., 756 
Malichite green hydrogenated, 603 
Malonie acid oond., 804 
Malonic anhydridci 873 
Malonic ester cond. aids., 804 
decom., 873 

Malonyl chloride in F. and C. syn., 893 
Maltose hydroL, 323, 325 
Manganese bromination cat., 52, 2&2 

in drying oils, 266 

oxidation cat., 52, 254 
Manganese chloride cat., 283 
Manganese dioxide cat. HiOi, 75 
Manganese oxides oxidation cat., 259 
Manganese salts cats., 100, 153, 264, 

269n 
Manganous acetate, 268 
Manganoiis borate, 265 
Manganous oxide cat., 259, 617, 702, 
828, 840, 845, 850, 853, 866 

on alcohols, 142 

dehydrogenation cat., 651, 672 

ketone cat., 840, 845, 850 
Manganous salts oxidation cats., 100, 

153, 264, 268 
Mannite est^., 757, 761 

by hydrogenation, 588, 595 

oxidised, 150 
Mannite hexacetate, 761 
Mannonic acid formed, 187 
Mannose isom., 186 

by oxidation, 150 
Margaric esters, 937 
Mechanical shaking, 562 
Mechanism of amine formation, 731 

of hydrogenation, 677 

of Grignard reaction, 300, 301 

of hydration, 308 

of mercaptan deoomp., 627 

of oxidation, 258, 264, 276 

of poisoning, 180^1808 

of promoters, 1809-180u 
Melissic add into ketone, 843 
Melting points of hardened oils, 966^ 

967n 
Menthane, 369, 449, 465, 475, 477, 478, 

518, 570, 591, 722 
Menthane^Uol, 463 



Menthene by dehydration, 714 

dehydzogimated, 644 

hydrogenated, 475 
Menthol, 436, 567 
Menthone hydrogenated, Pt 567 

by hydrogenation, 552, 591 

isom., 189 
Menthone-oxime hydrogenated, 385 
Mercaptans formed, 75, 170, 626-628, 

707n, 743-746 
Mercaptans, secondaiy, 628 
Mercaptides, 627 
Mercuric bromide bromination oat., 293 

hydration cat., 309 
Mercuric chloride with Al on alooholsy 
299 

with Al in F. and C. syn., 886 

bromination cat., 293 

hydration cat., 92, 309 

isom. cat., 92 

toxic to oats., 116 
Mercuric nitrate nitration cat., 269n 

oxidation cat., 269 
Mercuric salts red. with Pd, 165 
Mercuric sulphate hydration cat., 102, 
309 

oxidation cat., 272-274 

sulphonation cat., 6., 102, 816 
Mercury dec. HiOi, 180a 
Mercury oxide oxidation cat., 269n 
Mesaconic acid formed, 183 
Mesitylene with CO, 298 

hydrogenated, 447 

by isom., 888 

by polymer., 212 
Mesityi oxide, 697, 699, 797, 801 

hydrogenated, 420, 549, Ni 587, Pd 
546, 595, Pt 559, 567 
Meso-benso-dianthrone dehydrogen- 

ated,685 
Meso-naphtho-dianthrone, 685 
Meta-aldehydes depolym., 234 

formed, 222 
Meta-butanal formed, 223 
Meta-ehloral formed, 224 
Meta-heptaldehyde formed, 223 
Metanisobutanal formed, 224 
Metal chlorides as oats., 876 
Metal oxides as cats., 169, 675, 881 

dehydration cats., 686 
Metals, compounds formed, 299, 300 



392 



SUBJECT INDEX 



oond. of gases (m, 136 

in cracking, 906, 032 

decom. acetylene hydioearb., 913-019 

dec. aromat. hydrooarb., 921 

d^. esters., 867 

dec. formic acid, 823 

dec. formic eeten, 867 

dehydration cats., 686, 687, 701 

ketone cats., 830, 847 
Meta-propional formed, 223 
Metsrstyrene, 657 

Methane, 432, 495, 504, 536, 540, 593, 
620, 631, 634, 641, 645, 664, 672 

from COt by hydrogenation, 395-402 

from CO, 393 

deoom., Mg 920, Ni 911 

eqnilib. in formation, 409-411 

formed, 362, 369, 370, 377, 393, 395- 
402, 409-411, 413, 525 

formed from carbon, 586 

by hydrogenation, 362, 369, 370, 377, 
395-402 

oxidised, 253 
Methods of hydrogenation, 599 el seg. 
Methoxy-cydohexane, 464, 494 
Methoxy-methyl-cydohexanols, 464 
Methoxy-propylb^ueno, 590, 601 
Methoj^-propyl-cydohcoEane, 590 
Methoxy-propyl-phenol, 590 
Methyl acetate dec., 18Q; 

hydrol., 313 
Methyl-acetyl-Acetone hydrogenated, 439 
MethyhJ cond. with phenols, 792 

formed, 781 

by oxidation, 249 
Methyl alcohol, 432, 538, 740, 771, 773, 
851 

into aoetal, 781 

dehydrated, 688, 690, 691, 693, 713, 
715, 716 

dehydrogenated, 656, 676, CdO 674, 
MnO 672, Ni 664, SnO 673, Zn 678 

detection in EtOH, 656 

esterif., 771, 773 

from formic acid, 826 

oxidised, 249, 268 

with phenol, 789 

with Pt, 668 
Methyl-allene, 784 

Methyl-amine from HCN by hydrogena- 
tion 342, 528 



by hydrogenation, 377, 382, 510, 530 

oxidised, 256 
Methyl-amyl-aoetyleae, 308 
Methyl<«niline dec., 684 

formed, 729, 740 

hydrogenated, 468 
Methyl-anthracene from cracking, 909 
Methyl-anthraquinone nitrated, 260ii 
Methyl bensoate alcoholised, 340fi 

dec., 871 

by esterif., 744n, 766 

hydrogenated, 471 

into nitrile, 871 
Methyl-butadiene, 802 
Methyl-butane-diol dehydrated, 723 
Methyl-tert-butyl-amine, 430 
Methyl-butyl ketone hydrogenated, 435 
Methyl-butyl-phenol, 459 
Methyl-oarbyl-amine hydrogenated, 430 
Methyl-oarvacryl ether, 789 
Methyl-chlorcyclohexane, 660 
Methyl chloride in F. and C. syn., 884 
Methyl dnnamate hydrogenated, 601 
Methyl-p.cresyl ketone hydrogenated, 

389 
Methyl-oydohexane, 197, 447-450, 4i52, 
465, 467, 479, 660, 590, 641 

dehydrogenated, 641 

by hydrogenation, 388 

by isom., 197 
Methyl-f^dohexyl-amine, 739 
Methyl-cydohexanols into amines, 739 

dehydrogenated, "660 

by hydrogenation, 457 
Methyl-i^dohexanones by dehydrogma- 
tion, 660 

hydrogenated, 436, 567 
Methyl-cydohexanone-hydrasones, 611 
Methyl-<^dohexenes, 515, 660 
Methyl-<^dohexyl-amine, 467, 737, 739 
Methyl-cydohexyl-aniline, 467 
Methyl-oydopentane by hydrogenation, 

390,649 
Methyl cydopentane-carbonate, 649 
Methyl-cydopentanone hydrogenated, 

390,436 
Methyl-cydopropene hydrogenated, 472 
Methyl-diphenyl carbinol, 721 
Methylene chloride in F. and C. syn., 

896 
Methylene-dithiol, 492 



SUBJECT INDEX 



393 



Methyl eaten by alooho|y8U» 341 

deo., 860, 8d5, 871 
Blethyl ether, 688, 600, 601, 603, 718, 

805,871 
Methj^-ethyl-acetylene, 103 
Methyi-ethyl-Aoralelne hydrogenated, 

605 
Methyl-ethyl-amine, 430 
Methyl-ethyl4)eiisQoe by hydrogenatton, 
380 
from pinene, 022 
Methyl-ethyl-butadfeDe formed. 102 
Methyl-ethyl carbinol, 567 
Methyl-ethyl-eydohexene, 448, 440 
Methyl-ethyl-<^clohexene hjrdiogenated, 

475 
Methyl-ethyl ether, 601 
Methyl-ethyl-ethylene formed, 103 
Methyl-ethyl ketone hydrogenated, 567 
Methyl-ethyl ketone phenylhydraione 

dec, 633 
Methyl-ethyl-propenal hydrogenated 

546, 550 
Methyl-di-isopropyl-benxene, 030 
Methyl formate from aid., 228 
dec., 868 
by esterif ., 773 
Methyl-f urf urane hydrogenated, 487 

by hydrogenation, 371 
Methyl-heptanone by hydrogenation, 

420 
Methyl-heptenone hydrogenated, 420, 

552 
Methyl hezahydrobenioate, 471 
Methyl hezahydroterephthalate, 648 
Methyl-hezanone, 420 
Methyl-hexenone hydrogenated, 420 
Methyl-hexyl oarbinol dehydrogenated, 

665 
Methyl-hexyl ketone, 665 
Methyl-indol, 480, 633, 684 
Methyl-isobutjd-benaene by F. and C. 

syn., 000 
Methyl-isobutyl caibind, 540, 550, 568 
Methyl-ieobutyl ketone, 435, 545, 550, 

567, 587, 505 
Methyl-48opropyl-eyolohexaiie, 440, 475 
Methyl^ieopropyl ketone dehydrated, 
802 
hydrogenated, 435 
Methyl mercaptan, 744 



Methyl-naphthyl ketone hydrogenated, 

300 
Methyl nitrite hydrogenated, 382, 513 
Methyl-nonyl ketone hydrogenated, 435 
Methyl-pentanol, 550, 505 
Methyl-pentanone, 420 
Methyl-pentamethylene, 444 
Methj^-pentene hydrated, 306 
Methyl-pentyl alcohol, 540 
Methyl-phenyl-butine-ol hydrogenated^ 

548 
Methyl-phenyl caibind, 728 
Methyl-propyl carbincd, 487 
Methyl-propyl-octane by hydrogenation, 

166 
Methyl-propyl-ootene hydrogenated, 414 
Methji-propyl ketone hydrogenated, 

435 
by hydrogenation, 487 
Methyl-quinoline, 488 
Methyl-ealioylic aid. hydrogenated, 568 
Methyl tetrahydroterephthalate dehy- 
drogenated, 648 
Methyl-toluidines, 684, 740 
Methyl-valeric aid., 5^ 
Methyl-vanilline hydrogenated, 568 
Mexican petroleum cracked, 033 
MFB, 067n 

Migration of atoms, 100 
Migrations of double and trij^ bonds, 

100 
Mineral adds as cats., 81 
Mixed amines, 738 
Mixed catalysts, 538, 651, 675, 702, 826, 

827,866 
Mixed ethers formed, 170, 780 
Mixed ketones, 75, 847-^50 
Mixed oxide-catalysts, 538 
Mixed phenol-ethen, 788, 780 
Moisture in oils, 040 
Molybdenum chloride ohlorination cat., 

00,283,286 
Molybdenum compounds cats., 260n 
Molybdenum oxide cat., 675, 676, 603, 

702,827 
Molybdenum oxide, blue cat., 675, 746, 

701 
Molybdenum promoter, I8O0, 180u 
Monobasic adds dec., 820-854 
Morphine hydrogenated, 572 
,268 



391 



SUBJECT INDEX 



Mudo add dehydntod, 737 

68terif.,7M 

formed, 187 
Multirotation of migan, 188 
Mufltard oik hydxol., 333 
Mutton tallow, 038 
Myroene fonned, 214 
Myiistio add into ketone, 850 

Naphthalene oond., 806 

from oraddng, 008, 000 

deo., 021, 031 

dec., by AlCU., 031 

by dehydrogenation, 642 

fonned,008 

in F. and C. syn., 880, 800 

hydrogenated, 481, Ni 602, Pd 663, 
Pt671 

by hydrogenation, 370 

oxidised, 273 
Naphthalene hydrides from dHt, 014 

dehydrogenated, 642 
Naphthalic acids hydrogenated, 604 
Naphthalic anhydride hydrogenated, 

663 
Naphthane, 481 
Naphthenes formed, 211 
Naphthoic add est^., 766 
Naphthok into amines, 700 

hydrogenated, 481, 502 
Naphthol ethers hydrogenated, 404 
Naphthonitriles formed, 871 
Naphthoyl chlorides in F. and C. syn., 

800 
Naphthyl-amines, 512, 630, 632, 720 

hydrogenated, 406 

by hydrogenation, 370 
Naphthyl ethers, 780 
Naphthyl ketones by F. and C. syn., 800 
Natural gas, 028 
Negative catalysts, 0, 11 
Neutral salt effect in hydrd., 317, 310 

in inver. of sugar, 324 
Nickel, a, fi, and y forms, 360 

amount of required, 051 

carrier for, Pd 046 

on carrier, 126, 508, 030, 041, 042, 050, 
060 

cat, 15, 24, 53, 111-115, 122, 167, 
180{-180n, 343, 344, 358, 530, 540, 
563n, 584 et seq., 50(h603, 614, 610, 



620, 683, 721, 722 

oat. preparatian, 54-66, 506, 041 

in eraddng, 006, 010, Oil 

deo. GiHt, 013, 018-020, 025, 026 

dec aloohols, 180|^, 664 

deo. aldehydes, 610 

deo. amines, 631, 634 

deo. aromatic hydrooarb., 021 

deoomp. cat., 832, 834, 867, 010-913, 
018-021, 023, 025, 026 

deo. CO, 163 

dec. dilorides, 882 

dee. esters, 180b, ISV, 18Q/ 

dec. formic esten, 867 

deo. hydiooarb., 832, 834, 867, 01(V- 
013, 018-021, 023, 025, 026 

dee. ketones, 620 

deo. pinene, 023 

dehydrogenation cat., 636, 637, 640- 
645, 647, 651, 664, 665, 681, 684, 
701,824 

dim. NHs, 631 

in hardened oils, 060 

hydrogen comps., 167 

hydrogenation cat., 107, 801, 032, 030, 
041-045, 047, 048, 050, 051, 060 

hydrogenation cat. for fats, 030, 041- 
048, 050, 051 

isom. cat., 208 

from Ni(C0)4, 163, 508, 616, 042, 053 

preparation of, 53-66, 508, 041 

on pumice, 126, 030, 041, 042 

temp, for use, 052 
Nickd aoetate, 044 
Nickd borate cat., 266, 044 
Nickd carbonate, 041 
Nickd carbonyl, 163, 608, 616, 042, 053 
Nickd chloride cat., 283, 876, 880, 047 
Nickeled asbestos, 050, 060 
Nickded pumice, 126, 030, 041, 042 
Nickd formate, 044 
Nickd lactate, 044 
Nickd nitride, 375 

Nickd oxide oat., 76, 80, 254, 258, 250, 
722,043 

hydration oat., 310 

hydrogenation cat., 584, 508 

M. niokel, 584 

theory, 258 
Nickd peroxide, 180a 
Nickd sesquioxide, 580 



SUBJECT INDEX 



396 



Nickel Buboxida, 80, 608, 943 
Nickel sulphate ozid. oat., 272 
NitraniliDeB hydrogenated, Cu 613 
Nitration oatalyied, 269n 
Nitric add from NH«, 160, 240 

in hydration, 307 

hydrogenated, 376 

on metals, 8 

oaddifldng agent, 200 
Nitric oxide hydrogenated, 374, Cu 600, 

Pt6;20 
Nitrilee, 306, 633, 636, 681, 682, 808 

formed, 16, 631, 811, 812, 814 

hydrated, 311 

hydrogenated, 426-420, 621 

polymerised, 230 
Nitriles, aliphatic hydrogenated, 427 
Nitriles, aromatic hydrogenated, 428 
Nitroaoetophenone hydrogenated, 646, 

667 
Nitro-alcohols formed, 236 
Nitrobensaldehyde cond., 708 

by oxidation, 270 
Nitrobensene formed, 810 

hydrogenated, 378, 638, 646, Cu 611, 
Pd 636, 676, Pt 631, 637 

oxidising agent, 277 

solvent for F. and C. syn., 802 
Nitrobensophenone F. and C. syn., 803 
Nitrobenioyl chlorides in F. and C. syn., 

803 
Nitro compounds cond., 803 

from diaso, 600 

hydrogenated, 377, 378, Cu 600, Fe 
606, Ni 600, Pd 646, 676, Pt 620, 
667,664 
Nitro compounds, aliphatic hydrogen- 
ated, 377 
Nitro compounds, aromatic hydrogen- 
ated, 378 
Nitro-ethane cond., 236 

hydrogenated, 377, 610 
Nitrogen eliminated, 606-612 
Nitrogen dioxide hydrogenated, 620 
Nitrogen oxides hydrogenated, 620 
Nitrogen peroxide hydrogenated, 376, 

600 
Nitromethane cond., 236, 803 

hydrogenated, 377, Cu 610, Pd 636, 
Pt680 
Nitro-methanol-butanol, 286 



Nitro-methylol-propane-diol, 236 
Nitronaphthalene hydrogenated, 870, 

612 
NitroparaflSnes cond., 236 
Nitrophenols hydrogenated, 381, Cu 612, 
Pd636 

by oxidation, 260 
Nitrophenyl-ethylene, 803 
Nitropropane cond., 286 
Nitropropanol, 236 
Nitropropyl alcohol, 236 
Nitrosamines, 106 
Nitroso compounds as cats., 108 

hydrogenated, 664 
Nitroso-dimethyl-aniline in vulc, 104 
Nitroso-naphthol hydrogenated, 664 
Nitroso-phenol as cat., 106 
Nitroso-terpenes hydrogenated, 664 
Nitrostyrene hydrogenated, 666 
Nitrotoluenes hydrogenated, 378, Cu 
612, Pt 664 

by hydn^genation, 378 
Nitrous add cat., 82, 184, 260n 

esters of hydrogenated, 382, 600, 613 
Nitrous oxide hydrogenated, 368, 600 
Nonane by hydrogenation, 414 
Nonene hydrogenated, 414 
Nonylic add into aid., 862, 863 

into ketone, 846 
Nonylic aldehyde, 862-^64 
Nonylic esters dec., 871 

Ocdudon of gases, 180 

Odmene hydrogenated, 416 

Octadiene-diol hydrogenated, 666 

Octadiene-diolic add hydrogenated, 666 

Octane by hydrogenation, 414, 601 

Octane-diol, 666 

Octene hydrogenated, 414, Cu 616, Ni 

601 
Octodecyl alcohol, 666 
Octohydro-anthracene, 20, 363, 300, 483 
Octohydro-indol, 671 
Octohydr(H>henanthrene, 484, 686, 

602 
Octoic add into aid., 868 
Octoic aid., 863 

Octomethylene ring hydrogenated, 480 
Octo-trienal, 801 
Octyl alcohol, 666 
Octyl4)ensene hydrogenated, 660 



396 



StIBJECT INDEX 



Odon of oili elim. by hydrogenation, 

939,065 
Oeoanthaldoxime, 814 
Oenanthylidene hydrogenated, 425 
OenaBthylidene-Aoetic add hydrogen- 

ated,417 
Oils hydrogenated in vapor, 030 
Oils oxidised, 265 
Oklahoma petroleum cracked, 035 
Oleic add, ami. Hs required, 055 

in fats, 037 

hydiogenated, 422, 562, 030, 055, 
Cu 515, Ni 587, 601, Pd 546, 577, 
Pt 558, 565 

isom., 82, 184 

into ketone, 843 
Oleic esters in fats, 037 

hydrogenated, 577, 601 
Oleic alcohol hydrogenated, 565 
Olelne, 037, 030, 055 

amt. Hs required, 055 

into stearins, 030 
Olive oil hardened, 066 

iodine number, 038 
Optical isomers, 186 
Organic Mg compotmds, 300-302 
Origin of petroleum, 025-028 
Osmium cat., 64, 251 
Osmium black, 583 

Osmium oxide hydrogenation cat., 80, 
583 

oxidation cat., 262, 271 
Oxal-acetic add by oxid, 268 
Oxalic acid cat., 106 

dec, 12, 855 

dec. formic, 822 

esterif., 758 

by oxidation, 260 

oxidised, 246 

retarder, 11 
Oxalic esters dec., 873 
Oxamide, 105, 312 
Oxidation, 64, 150, 152, 244-277 

catalysts, 50, 60, 100, 152, 162, 245- 
267 

by chlorates, 271 

with gaseous oxygen, 244-267 

by hydrogen peroxide, 268 

by hypochlorites, 270 

by nitric add, 260n 

by nitrobensene, 277 



by permanganates, 275 

by persulphates, 276 

by sulphur trioxide, 272 

of oils, 266 

of phenols, 11 
Oxides, carriers for, Pd 046 

catalysts, 73, 75, 784, 780, 807-^800, 
813, 823, 837, 848, 858, 006, 021, 034 

in cracking, 006, 034 

dec. hydrocarb., 006, 021, 034 

dehydrogenation cats., 638, 780 

hydrogenation cats., 508 

ketone cats., 848 

prep, of, 76 
Oxides of carbon hydrogenated, 504 
Oxides of nitrogen cats., 260n 

hydrogenated, 374 
Oximes hydrogenated, 383, 514 

hydrolysed, 332 
Oxygen absorbed by 0, 1806, by Au, Pt 

and Ag 137 
Oxygen in catalysts, 165, 563, 563n, 
043n 

in Pt black, 563 
Oxygenation of cat., 043n, 047n 

Palladium absorbs hydrogen, 136, 150, 
165 

on alcohols, 660 

on aldehydes, 623 

amotmt of required, 051 

black, 251, 562, 573^70, 822 

cat., 65, 126, 260n 

ooUddal, 71, 141, 544r555, 604 

colloidal prep, of, 71 

dehydrogenation cat., 648, 640, 651, 
660,824 

hydrt^genation cat., 534, 536-505 

in hydrogenation of fats, 046 

poisoned, 180o 

polymeric., 212 

sponge, 604 

temp, of use, 052 
Palladium black, 251, 562, 573^70, 822 

palladium hydride, 150 
Palladium sponge, 604 
Palladous chloride, 562 
Palm oa bleached, 265 
Palmitic esters, 037 
Parabutanal formed, 223 
Paraldehyde cond., 801 



SUBJECT INDEX 



397 



crotonised, 796, 801 

depolymeiued, 234 

fonned, 82, 104, 222, 223, 724 
Para-indene formed, 217 
Paiapropional, 223 
Peanut oil, 938 

hardened, 906 
Pelargonic acid into aldehyde, 852 

Mterif 771 
Pennsylvania petroleum cracked, 911 

nature of, 925 
Pentachloipropane, 242 
Pentachlorpropylene formed, 879 
Pentadecyl-benxene hydrogenated, 509 
Pentameihylene ring hydrogenated, 474 
Pentarisobutanal formed, 224 
Pentamethyl-benxene dee. F. and C, 

887 
Pentane from CiHs, 211 

dec. by Ni, 911 

formed, 211, 558, 505, 931 
Pentane-diol dehydrated, 720 

by hydrogenation, 595 
Pentane-thiol, 745 
Pentol-H>ne, 439 
Perchlorb^uene reduced, 404 
Perchlorethane prep., 289 
Perchlormethyl mercaptan, 278n 
Perhydroanthraoene, 29, 303, 483, 592 
Perkin's syn., 107 

Permanganates aa oxidising agents, 275 
Peroxides as intermediate oomps., 150- 

153 
Persulphates oxid. agts., 270 
Perylene, 085 
Petroleum cracked, 254n 

by AlCk, 935 

formation, 500, 925-928 
Phellandrene, 196 
Phenanthrene oond., 800 

from cracking, 909 

hydrogenated, 484, 042, Ni 592, Pd 
530, 579, Pt 571 
Phenanthridene oxidised, 270 

by oxidation, 270 
Phenetol, 404 
Phenol from bentene, 150, 843 

from bromphenols, 405 

from chlorphenols, 404 

dehydrated, 10, 785 

bydiaso, 000 



by dehydrogenation, 042 

ethers of formed, 75, 904, 785-789 

formed, 150, 293, 404, 405, 843 

hydrogenated, 120, 444, 450, Ni 003, 
Pt509 

by hydrogenation, 381 

by oxidation, 203, 268 

into thiophenol, 791 
Phenol ethers formed, 785-789 

hydrogenated, 494 
Phenols with aldehydes, 792 

condensed, 803 

dehydrated, 785, 789 

hydrogenated, 370, 450, 003 

nitrated, 200n 
Phenolic i^ucosides, 793 
Phenylactaldehyde by dehydrogenation, 
057 

hydrogenated, Pd 549, Pt 500 
Phenyl acetate dec., 871 
Phenylacetic add into aid., 853 

dec., 830, 839 

esterif ., 750-758 

hydrogenated, 471 

into ketone, 843-845, 850 
Phenyl-acetylene hydrogenated, 451, 

Cu520,Pd548 
Phenyl-alkyl ethers formed, 789 

hydrogenated, 404 
Phenylation of amines, 032 
Phenyl-bensyl carbinol dehydrated, 714 
Phenyl bromide in syn., 901, 904 
Phenyl-butyl chloride in F. and C. syn., 

897 
Phenyl-carvacryl ether, 788 
Phenyl chloride in syn., 904 
Phenyl-p.cresyl carbinol red., 309 
Phenyl-cresyl ethers, 788 
Phenyl-p.cresyl-methane by hydrogena- 
tion, 309 
Phenyl-cydohexane, 452, 475 
Phenyl-cydopentane by F. and C. syn., 

897 
Phenyl-cydohexane formed, 889 

hydrogenated, 475 
Phcnylene diamines by hydrogenation, 

380 
Phenylene-naphthalene oxides, 788 
Phenylene sulphide formed, 2^5 
Phenyl esters dec., 871 
Phenyl ether, 338, 785-787 



398 



ST7BJECT INDEX 



hydrogenated, 494, (Sd9 

fonned, 59, 75, 786, 904 
Phenyl ethen, 785-788 
Fhenylethyl alcohol dehydrogenated, 657 

hydrogenated, 369 

by hydrogenatioii, 560 
Fhenylethyl chloride in F. and C. syn., 

897 
Phenyl-ethylene hydrogenated, 415, 451, 
516 

by hydrogenation, 520 
Phenyl-ethylene hydrocarbons hydro- 

genated, 415 
Phenyl-ethyl ketone hydrogenated, 539 
Phenyl-glycolic add eeterif ., 756 
Phenylhydrasine dec., 91, 611 

from phenylhydrasoncB, 332 

hydrogenated, 497 

negative cat., 11 
Phenylhydraionee dec., 633, 635 

hydrol., 332 
Phimyl-hydroxy-crotonic add, 203 
Phenyl iodide in syn., 904 
Phenyl-iflocrotonio add hydrogenated, 

417 
Phenyl ieocyanate hydrogenated, 495 
Phenyl-naphthyl-amine, 632 
Phenyl-naphthyl ketone hydrogenated, 

685 
Fhenyl-nitroeamine formed, 206 
Phenyl oxide by diaso, 59 

formed, 75, 338, 785-787, 904 

hydrogenated, 494, 589 

hydrol., 16, 338 
Phcoiyl-naphthyl ethers, 788 
Phenyl-pentyl chloride in F. and C. 

syn., 897 
Phenyl-propiolic add hydrogenated, 548 
Phenyl-propionic add, 417, 546, 560, 580, 
581, 594, 601 

dec, 839 

into ketone, 844 
Phenyl-propyl alcohol, 560, 568 
Phenyl-propylene by hydrogenation, 384 
Phenyl-propyl-pentane by hydrogena- 
tion, 415 
Phenyl-propyl-pentene hydrogenated, 

415 
Phenyl-pyridines, 807 
Phenyl sulphide formed, 295 
Phorone by cond., 797 



hydrogenated, 420, Pd 547, 549, Pt 
567 
Phosgene formed, 134, 282, 282n, 284 
Phosphine cat., 7B0 

cat. poison, 180p 

formed, 700 
Phosphoric add cat., 687, 689, 691, 696 
Phosphorus cat., 46, 687 

dilorination cat., 281 

oxidised, 150 

toxic to cats., 115, 116 
Phosphorus, red dehydration cat., 700 
Phosphorus trichloride chlorination 

cat., 281 
Phthalelnes, 90 
Phthalic add esterif ., 756 

hydrogenated, 392, Ni 590, Pt 563, 569 

by oxid., 273 
Phthalic anhydride cond., 107 

by oxid., 260n, 273 
Phthalid by hydrogenation, 392 
Phthalimide hydrogenatied, 569 
Phthalophenone by F. and C, 893 
Phthalyl-acetic add, 107 
Phthalyl chloride in F. and C. syn., 893 
Phydcal cond. of oat., 41, 53^65, 76-80, 

703 
Phydcal theory of catalysis, 131 et mq, 
Pl^rtane, 565 

Phytene hydrogenated, 565 
Phytol hydrogenated, 565 
Picoline, 680 
Pinacoline, 724 
Pinacones, 195, 724, 726 
Pinane, 552, 591, 594 
Pinene cracked, 909 

dec, 235, 909, 922, 923 

dehydrogenated, 664 

hydrated, 307 

hydrogenated, 477, Cu 594, Ni 591, 
Pd 552, Pt 570 

isom., 198 

polym., 216 
Piperidine, 486, 555, 561 

alkylated, 741 

cat., 804, 836 

dehydrogenated, 647 

in vulc of rubber, 104 
Piperonal hydrogenated, 568 
Piperonal-acetone hydrogenated, 565 
Piperonyl-acrylic add hydrogenated, 601 



SUBJECTT INDEX 



399 



Piperonjd-propioiiie add, 601 
Piperylene by dehydration, 726, 784 

polym., 213 
Pittsburi^ gas, 028 
Platinum absorbs Qt, 137 

asbestos, 247 

catalyst, 61, 76, 126, 180e, 342, 589, 
563n, 616, 829 

in oombustion anal., 250 

in eraddng, 906 

dec. acetylene, 913, 914, 920 

dec. alcohols, 668 

dec. aids., 62^ 

dec. ethylene, 912 

dec. formic esters, 867 

dehydrogenation cat., 636, 637, 643, 
649, 651, 668 

hydn^S^iation cat., 524-535, 945 

moss, 524 

oxidation cat., 4, 15, 61, 154, 235, 245, 
255, 249, 250, 255, 256 

oxidation cat. for SOs, 4 

poisoned, 180a 

spiral, 829 

wire, etc., 249 
Platinum black activity of, 63 

cat., 235, 246, 247, 445, 562 

dee. HsOs, 2 

deoxidising, 14 

heat weakens, 63 

hydrogenation cat., 344, 524, 563^72 

oxidation cat., 1, 14 

poisoned, 117, 947n 

preparation, 61 
Platinum chloride cat., 635 
Platinum, coUoidal, 69, 72, 141, 248, 544, 
556^561 

poisoned, 116 
Platinum moss, cat., 624 
Platinum sponge cat., 193, 245, 342, 445, 

624, 637, 824 
Poisoning of catalysts, 112 et seg., 180a- 
1808, 946, 947n 

of Ni cat, 112, 598 

of Pt cat., 116 
Poly-alcohols dehydrogenated, 680, 723, 

727 
Poly-aldehydes formed, 222 
Poly-alkyl-bensenes dee., 887 
Poly-ethyl-benxenes dec. F. and C, 

888 



Polyt^clic hydrocarbons hydrogenated, 

432 
Polymerisation, 89, 209-233 
Poljrmethylene hydrocarbons, 535, 926, 

927 
Polymethylene rings hydrogenated, Pt 

535 
Pol3rpheno]s hydrogenated, 460 
Pol3rphenyl hydrocarbons hydrogen- 
ated, 452 
Polysaccharides hydro!., 323 
Polyterpenes from cracking, 909 
Polyvalerylene formed, 212 
Poppyseed oil, 938, 966 

hardened, 966 
Porous substances, 139 
Potash as cat., 611, 796 
Potassium cat. polym. hydrocarbons, 

213, 232 
Potassium acetate cat., 107 
Potassium bisulphate cat., 97, 687, 726 

cat. eeterif ., 759, 760, 783 
Potassium chloride cat., 876 
Potassium cyanide in aldolisation, 95 

cat., 230 

toxic to Pt, 117 
Potassium copper cyanide cat., 95 
Potassium f erricyanide reduced with Pt, 

165 
Potassium formate, 823 
Potassium hydroxide cat., 799 
Potassium iodide cat., 94 
Potassium soaps toxic to cats., 115 
Preparation of catalysts, 54-56, 58, 59, 
77, 78, 598, 606, 655, 704, 705, 941, 
942 
Pressure, effect of, 30 

on dehydration, 711 

on hydrogenation, 946, 956 

on hydrolysis, 317 

on inversion of sugars, 324 
Primary alcohols dehydrogenated, 650 
Promoters, 1808-180u 
Propane from ethyl acetate, I8Q7 

by hydrogenation, 414, 472, 912 
Propane-thiol, 745 
Propenol hydrogenated, 416 
Propionamide hydrogenated, 386 
Propionic add dec., 838 

eeterif., 761, 771 

by hydrogenation, 417 



400 



SUBJECT INDEX 



into ketone, 840, 842-845 
Propionic aldehyde, 416, 419, 668, 664, 
668, 680, 839 

oond., 796, 808 

orotoniied, 796 

dec., Cu 621, Ni 620, Pd 623, Pt 622 

into ester, 228 

formed, 208, 249 

hydrogenated, 432 

by oxidation, 249 

polym., 223 
Propionic aldehyde phenylhydraione 

dec., 633 
Propionic anhydride into ketone, 867 
Propionic eeten dec., 863, 871 
Propionitrile cat., 606 

polym., 231 
Propionyl chloride cond., 902 

into nitrile, 813 
Propiophenone-ozime hydrogenated, 384 
Propyl acetate dec., 861 
Propyl-acetylene formed, 192 
Propyl alcohol, 416, 419, 668, 680, 740, 
741 

into acetal, 780 

into amine, 732 

dehydrated, 691, 694, 700, 713, 715- 
717, 719 

dehydrogenated, 666, MnO 672, Ni 
664, Pt 668 

eeterif., 761, 771, 773, 776 

by hydrogenation, 416 

ozidiaed, 249, 264, 268 
Propyl-amine from ale, 733 

by hydrogenation, 382 
Propyl-benxene by hydrogenation, 384, 

448, 639, 660 
Propyl bensoate, 766 
Propyl bromide isom., 199 
Propyl chloride dec., 877 

isom., 199 
Propyl cyanide aa cat., 606 
Propyl-cydohexane, 449, 690 
Propyl formate, 773 

Propylene, 691, 694, 696, 700, 713, 716, 
736 

from CiHs, 916 

dec., Ni 912 

formed, 877, 916 

hydrated, 306n 

hydrogenated, 414, 616, 626 



Prt^yl ether, 091, 694 
Propyl iodide, 606 
Propyl-iaoamyl-«mine, 738 
Propyl malonate dec., 873 
Propyl mercaptan, 744 
Propyl-methoxy-eydoheacanol, 660 
Prt^yl-methozy-idienol, 603 
Propyl nitrite hydrogenated, 382 
Propyl oxalate dec., 873 
Propyl phenyl ether, 780 
Propyl-piperidine, 741 
Propyl propionate from aid., 228 

dec., 861 

by eeterif ., 761 
Propyl succinate dec., 873 
Protocatechuic aid., by ozid., 268 
Pieudocumene hydrogenated, 447 

isom., 888 
Pseudoionone, 800 
Peeudomorphine by oxid., 268 
Pulegomenthol, 436, 667 
Pulegomenthone, 421, 436 
Pulegone, dehydrogenated, 646 

hydrogenated, 421, Ni 691, Pd 662, 
Pt 667 
Pumice cat., 811, 828 

carrier, 126, 598 
Purification of oils for hydrogenation, 

947-949 
Pyridine cat., 187, 224, 836 

by dehydrogenation, 647 

in F. and C. syn., 893 

hydrogenated, 486, Pd 656, Pt 661 

oxidised, 267 

sulphonated, 816 

in syn., 893, 901 
Pyridine^sarbonic add hydrogenated, 

561 
Pyridine homdogs hydrogenated, 561 
I^ridyl-phenyl ketone by F. and C. syn., 

893 
Pyrocatechol hydrogenated, 370, 461 

by oxid., 268 
Pyrogallol hydrogenated, 462 

oxidised, 160 
Pyrogenetic equilibria, 906 
Pyrography, 249n 
PyrcHnudc aid. hsrdrogenated, 434 
Pyrone formed, S35 
Pyrrol, 686, 807 

alkylated, 742 



N 



SUBJECT INDEX 



401 



hydrogenated, 486, 571 
'Pynoh oond., 808, 806 
PynoUdine, 429, 485, 571 

Quantity of oat., 32 
Queroetine by hydrd., 328 
Qiiinaldine hydrogenated, 488 
Qumalisanxie by ozid., 274 
Quinidme hydrogenated, 555 
Quinine aa cat., 836 

hydrogenated, 604 
Quinine sulphate hydrogenated, 572 
Quinite, 461, 589 

dehydrated, 723 
Quiniaarine by ozid., 274 
Quinoline ae cat., 187, 703, 836 

by dehydrogenation, 647 

in F. and C. lyn., 803 

hydrogenated, 488, 480, Ni 502, Pd 
555, Pt 561 
Quinone hydrogenated, 442 

by oxidation, 276 
QuinoneB hydrogenated, 442 

Radiation theory of oatalyBie, 18Q; 
Reaction tube for catalysts, 347 
Reciprocal catalysis, 146 
Regeneration ci catalysts, 123-125, 

563n, 032, 047n, 050 
Regeneration of thoria, 7QSn 
Resinous substances by oxidation, 266 
Resordne cond., 806 

hydrogenated, 370, 461 
Reversible reactions, 10, 30 
Rhodium cat., 64 
Rhodium black cat., 822 

in hydrogenation, 581 
Ribonic add foimed, 187 
Rich^ gas., 307 
Ricinoldc add, 037 
Ridnolelc esters, 037 
Ring fonnation, 82, 104, 684, 685, 727, 

806 
Rubber syn., 106, 213, 214, 784 

▼ulcanis., 104 
Ruberythrio add hydrogenated, 328 
Russian petroleum cracked, 034, 036 
Ruthenium cat., 64 
Ruthenium blad^, 580 

Sabinene hydrogenatecit 570 



Sacdiaric add dehydrated, 727 

Saf rol hydrogenated, Ni 590, Pt 565 

8alicine,320 

BBheyVie add esterif ., 756-757 

by hydroL, 328 
Baligenine by hydroL, 320 
Saliretine by hydrd., 320 
Sand cat., 606, 811 
Sandmeyer reaction, 01, 600 
Santonin hydrogenated, 571 
Si^Kmification, 17, 305, 337 

add radical influence, 316-310 

of esters, 337 

of fats, 314, 310 

neutral salt influence, 317 

theory ci, 176 
Saturated hydrocarbons by hjrdrogena* 

tion, 412^15 
Schlinck's apparatus, 060 
Schwoerer's apparatus, 050 
Sebadc add into ketone, 843 
Secondary alcohols, 420 

dehydrogttiated, 650, 650 

esteiif., 766, 775 

prep., 435 
Secondary amines by hydrogenation, 
383 

from naphthols, 700 

pnp., 427 f 732 
Sdective absorption by cats., 180% 
Sdenium hydride toxic to cats., 180o 
Selex, 067n 

Separation of carbon, 613 
Sesame oil, 038 

hardened, 066 
Sesquiterpttifis hjrdrogenated, 570 
Side chains hydrogenated, Cu 504, Ni 
500 

Silica cat., 75, 78, 540, 675, 676, 702, 811, 
825,011 

dec. formic add, 624 

ketone cat., 847 

ptBp.f 705 
Silica gd cat., 75n, 180e, 77291 
Silicates cat., 00, 267 

ketone oat., 847 
Silver aboorfoa Qi, 137 

oat., 60 

with 00, 615 

deo.W>«,34 



4021 



SUBJECT INDEX 



oaddatioD oat., 282, 264, 259 
Silver chloride oat., 876 
saver colloidal, 70, 72 
Silver nitrate cat., 276 
Silver oxide cat., 276 
Silver salts in nitration, 269ii 
Site of grains, 36 
Skatol,647 
Snow drift, 967n 
Soda dehydration cat., 79S 
Sodium isom. cat., 60 

polymer, cat., 60, 213, 231, 232 
Sodium acetate d«iAiydration cat., 107, 
706 

esterif . cat., 748, 761 

polym. aids., 224 
Sodium alcolu^te cat., 340ii 
Sodium borate cat., 674 
Sodium carbonate to neut. oils, 948 
Sodium chloride cat., 876, 964 
Sodium fonnate cat., 822 
Sodium hydroxide ddiydration cat., 796, 

798 
Sodium methylate cat., 799 
Sodium nitrate efifect on Ni, 947 
Sodium sulphide toxic to cats., 947 
Sodium thiosulphate in isom., 182 
Solvent naphtha cracked, 909 
Solvents as cats., 36, 37, 40 

in hydrogenation, 699 

influence of, 38-40, 18Qf 

influence on equilibra, 39 

influence on inversion of sugars, 324 

influence on reaction velocity, 38 
Sorbio add hydrogenated, 668 
Sorbite, 688, 696 
Sorbose formed, 186 
Spedfidty of cats., 142 
Spirocyelane hydrogenated, 636 
Squibb's method, 161 
Stabilisers, 13 
Stannic chloride aoetylation cat., 240 

chlorination cat., 283, 288 

cond. cat., 243 

in F. and C. ^n., 899 
Stannic oxide ketone cat., 849 
Stannous oxide cat., 288, 639, 676 

dec. alcohols, 673 

dehydrogenation cat., 673, 824 
Starch cat., 269n 

hydrolyaed, 4, 323, 326 



State of cat., 41, 63-66, 76-80 - 
Stearic add, 422, 616^ 646, 668, 662, 677, 
687,601 

into ketone, 843, 847, 860 
Stearic esters, 937 
Stearine, 937 
Stearone, 847 

Steaiyl diloride hydrogenated, 676 
Stibine dec., 8 

toxic to cats., IBOo 
Stilbene 1^ dehydration, 714 

hydrogenated, 416, 616 

by hydrogenation, 648 
Stining in hydrogenation, 687fi, 601 
Stoichiometric theory of catalysis, 180a 
Strontium carbonate cat., 838 
Stiychnine hydrogenated, 666 
Styrene from acetylene, 914, 916 

fonned, 241, 620, 648, 667, 889 

hydrogenated, 416, 461, Cu 616, Pd 
646, Pt 669 
Suberic add, 666 

into ketone, 843 
Succinic add esterif., 766 

by hydrogenation, 646 
Succinic anhydride formed, 878, 874 

hydrogenated, 392 
Succinic esters decom., 873, 874 
Suodnimide, 312 

Succinoyl chloride in F. and C. qm., 883 
Sucrose hydrol., 323, 324 
Sugar oxid., 269 
Sugars formed, 236 

by hydrol., 323 

inverted, 176 

isom., 186 

multirotation of, 188 
Sulphates effect on, Ni 947 
Sulphides, 743, 744 
Sulphocyanic esters, 333 
Sulphonation, 816, 816 

aided by ^SO^, 102 
Sulphur added, 296, 296 

catalyst, 6, 46, 630 

chlorine cat., 280 

elxnunated from petroleum, 933 

toxic to cats., 116, 116, 947 
Sulphur compounds in hydrogenation, 
669 

toxic to cats., 946 
Sulphur dioxide added, 87, 297 



SUBJECT INDEX 



403 



cat., 74 

ozidifled with Pt 4, 247 

polym. aids., 222 
Sulphuric add on alcohols, 159 

catalyst, 687, 689, 691, 696, 713 

cond. agt., 795, 803 

ineeterif., 748, 749, 751, 7^, 756, 
758 

on foimald., 822 

In hydration, 306, 308 

isom. terpenes, 198 

manufacture, 32, 158 

by oxidation, 258 
Sulphuric add fuming as oxid. agt., 272- 

274 
Sulphur trioxide oat., 12 

manuf ., 247 

oxidising agt., 272 
Sunlight in chlorination, 281n 
Surface, importance of, 35 
Sylvestrene hydrog^iated, 477 
Synthetic tallow, 967 

Tagatoee formed, 186 
Talgol, 967 
Tallow, 938 

hardened, 966 
Talomudc acid, 187 
Talose formed, 186 
Tartaric add esterif ., 756 

toxic to cats., 115 
Tellurium oxid. cat., 45, 251 
Tellurium hydride toxic to oats., IBOo 
Temperature coef . in dehydration, 709 

coef . of reactions, 24, 25 

effect on hydrocarbons, 905 

of hydrogenation, 361, 952 

of prep, of cats., 707n 

regulation, 348 
Terephthalic add, 648 
Terpenes dec., 922 

dehydrogenated, 643 

hydrogenated, 477, Ni 591, Pt 570 

isom., 198 
Terpine, 307, 308 
Terpinene formed, 198 
Terpineol dehydrogenated, 645 

hydrogenated, 478, 552 
Terpinolene formed, 198 
Tertiaiy alcohols esterif., 778 
Tertiary butyl alcohol oxidised, 249 



Tetra-aoetyl^phenyl-glucodde, 793 

Tetra-amylene fonned, 211 

Tetrabromethane in F. and C. qm., 897 

Tetrachlorethane dec., 881 
formed, 199 
insyn., 903 

Tetrachlorethylene formed, 879 

Tetracosene formed, 210 

Tetra-ethyl-ammonium iodide, 38 

Tetrahydro-acenaphthene, 482 

Tetrahydro-«uithracene, 29, 363, 483, 
592,642 

Tetrahydrobensoic add, 476 

Tetrahydrocarvone, 552, 567 

Tetrahydrocolchicine, 555 

Tetrahydrodoremone, 570 

Tetrahydrofurfuryl-ethyl caibinol, 487 

Tetrahydroionones, 554 

Tetrahydro-methyl-furf urane, 487 

Tetrahy dro - metiiyl - naphthalene - car- 
bonic add, 5^ 

Tetrahydronai^thalene, 379, 481, 481*^ 
571, 592, 594 

Tetrahydronaphthdo add, 594 

Tetrahydronaphthalid, 563 

Tetrahydrophenanthrene, 484, 536, 579, 
592,642 

Tetrahydrophenol, 723 

Tetrahydropiperine, 555 

Tetrahydroquinoline, 488, 561, 592 
dehydrogenated, 647 

Tetrahydroeantonine, 571 

Tetrahydrostiychnine, 555 

Tetrahydroterephthalic add, 648 

Tetrahydroxyanthracene oxid., 274 

Tetrahydro}Qrflavanol by hydroL, 328 

Tetra-isobutanal formed, 224 

Tetralin, 481n 

Tetramethyl-beniene dec., F. and C.| 
887 

Tetramethyl-diamino-benslgrdrol cond,, 
730 

TetramethyMeucaniline, 730 

Tetramethylene-diamine, 429 

Tetramethylene ring hydrogenated, 473 

Tetraphenylethane, 538, 662, 720 
hydrogenated, 463 

Tetraphenylethylene, 736 

TetroUc add hydrogenated, 546 

Thalium cat., 47 

Thalium chloride chlo. oat., 283 



404 



8T7BJECT INDEX 



Theories ci oatalyne, 129 et mq., 131, 

146, 180, 18a»-180u 
Theory of dehydration, 786 
Theory of eeterificatioa, 762, 762, 768 
Theory of eiter deoomp., 869^864, 866, 

872 
Theory of poiiioning catalysts, 180o 
Thianthrene, 629 
Thiobenaophenone qm., 894 
Thiodinaphthyl-aminee formed, 296 
ThiodipheDyl-amine formed, 296 
Thio-indigo hydrogemited, 603 
Thiophene formation, 686, 810 

toxic to cats., 112, 947n 
Thiophenol formed, 296 
Thiophenols dec., 629 

formed, 296 
Thiophosgene in F. and C. syn., 894 
Thiols formed, 75, 743-746 
Thiourea isom., 207 
Thioureas, 630 

Thoria catalyst, 16, 24, 75, 79, 143, 170, 
638, 676, 693, 700, 702, 707, 716, 
720, 731-738, 813 

aldehyde oat., 864 

dec. dilorides, 881 

dee. esters, 868, 861, 861n, 864-^66, 
872, 873, 1806, 18qf, I8Q7, 180n 

dee. formates, 870 

dehydration cat., 651, 743-746, 788, 
789, 791, 801, 808, 809 

dehydrogenation cat., 686 

esterif. cat., 764-766, 772 

hydrolysis cat., 337, 338 

life of, 708 

ketone cat., 840, 844, 848, 850, 857 

mercaptan cat., 746 

mixed cat., 826 

preparation of, 707n, 861n 
Thorium chloride cat., 90 
Thujane, 670 
Thujone hydrogenated, 478, 652, 570 

isom., 198 
Thymol, ethers of, 789 

formed, 646 

hydrogenated, 459 
Thymoquinol hydrogenated, 463 
Thymoquinone hydrogenated, 442 
Tin chlorination cat., 47, 288 

dehydrogenation cat., 673, 824 
Tin chlorides aeetylation oat., 240 



chkrinatbn cats., 288, 288 

oond. cat., 243 
Tin oxides ddorination cats., 288 

dehj^dration cats., 702 
Titania eats., 76, 143, 337, 624, 693, 
702, 704, 709, 732 

aldehyde oat., 862 

in cracking, 906, 934 

dee., alcohols, ISOg 

dec. esters, 180b, 19V, 18(V, I8O11, 
861n, 863, 864, 868 

dehydration cat., 826 

dehydrogenation oat., 686 

esterif. eat., 766, 767, 771, 772, 776 

hydrolyt. eat., 686 

ketone cat., 849 

mixed cat., 675, 676 

prep, of, 704, 861n 
Tolane, hydrogenated, 648 
Toluene, 465, 660, 590, 693, 641, 667, 
681 

brominated, 292, 293 

chlorinated, 278, 281, 286 

from cracking, 906, 909 

from cresoles, 370 

from cymene, 930 

dec. by F. and C, 887 

by F. and C. syn,, 884 

in F. and C. syn., 899 

hydrogttiated, 444, 447, Pt 634, 660, 
569, Rh 581, Ru 580 

by hydrogenation, 369, 388 

oxidised, 257, 260n, 263 

from petroleum, 934 

from pinene, 922 
sulphonated, 816n 

from xylene, 930 
Toluic adds dec., 830 

esterif., 758, 766 

into ketones, 848, 849 
Toluic aldehydes dec, 623 

syn., 296 
Toluic esters dec., 864, 871 

hydrogenated, 471 
Toluidines, 497, 664, 630-632, 683, 684, 
790 

alkylated, 740 

hydrogenated, 467 

by hydrogenation, 380 

manufacture of, 512 
1,266 



SUBJECT INDEX 



406 



Tduonitrik hydrogenated, 42S 
Toluquinone hydrogeoated, 442 
Tolyl-dimethjd oarbinol hydrogon&ted, 

360,465 
Tozio subfltanoes removedi 947-049 
Toxicity of CO, 953 
Toxicity scale, 116 
Trade names of hardened oils, 967 
Trehalose hydro!., 323, 325 
Triaoetin, 760 
Tri-aniylene formed, 211 
Tribromphenol, 293 

hydrogenated, 405 
Tributene formed, 210 
Trichlorbensene, 404 
Trichlor-tert.butyl alcohol, 238 
Trichlorethylene cond., 242 

formed, 881 
Triohlorethyl trichloraoetate, 228 
Trichlorphenol, 404 
Trioydohexyl-methane, 463 
Triethyl-amine cond., 38 

formed, 377, 427 
Triethyl-amine hydrochloride cat., 783 
Triheptene, 519 
Tri-isoamyl-^mine, 682 
Trimethyl-amine cat., 224 

formed, 377, 496 
Trimethyl-benaenes dee., 887 
Trimethyl carbinol dehydrated, 713, 
719 

esterif ., 776 

into ether, 691 

formed, 306 
Trimethyl-cyciohexaneB, 449 
Trimethylene bromide, 605 
Trimethylene ring hydrogenated, 472 
Trimethyl-ethylene dee., Ni, 912 

formed, 190 

hydrogenated, 414 

polym., 210 
Trimeth^-hydrozy-butyl-oyolohexane, 

560 
Trimethyl-nonenone hydrogenated, 420 
Trimethyl-pentane by hydrogenation, 

414 
Tiimethyl-pyrasoline formed, 196 
Trioxymethylene into aoetal, 781 

cond., 792, 806 

formed, 432 

in syn. rubber, 215 



Triphenyl oarlunQl reduced, 869 
Triphenylene, 646 

Triphenyl-methane formed, 869, 728, 
890 

hydrogenated, 453 
Tungsten as promoter, 180» 

filament, 180», 180p 
Tungsten, blue oxide, cat., 24, 693, 825 

dehydration cat., 651, 791 

on formic acid, 624 

mercaptan eat., 746 
Tungstic oxide, 75 
Turpentine oxid., 151 
Types of hydrogenation apparatus, 957, 
964 

Undecenal, 658 
Undecenyl alcohol, 658 
Undecylenic add hydrogenated, 417 
Undecylic add, 417 
Unsaturated adds esterif., 756 

hydrogenated, 422 

isom., 203 
Unsaturated alcohids hydrogenated, 416, 
418, 419 

into sat. aids., 208 

into cat. ketones, 208 
Unsaturated chlorides dec., 876 
Unsaturated esters, 937 
Unsaturated hydrocarbons, 743, 764, 
802,866 

dec., 912 

formed, 75, 142, 169, 695 et mq., 871, 
872, 876, 878 

hydzated, 305 
Unsaturated ketones hydrogenated, 420, 

602 
Uranium in drying oils, 266 

as promoter, ISOs 
Uranium chlorides eats., 90, 283 
Uranium oxide cat., 75, 260, 702 

dec. alcohols, 142 

ketone cat., 840, 849 

oxidation cat., 259 
Uranous oxide eat., 675, 676, 726, 
825 

dehydration cat., 791 

mercaptan eat., 746 
Uranium soaps toxic to oats., 115 
Urea aoetylated, 87 
Urethane oxid., 259 



406 



SUBJECT INDEX 



Msid irom aloohol, 150 

into ketone, S43, 845 
Vftlflrio esten dec, 863 
Valerolactone, 437 
Valerane, 547, 549 
Valerylene polym., 212 
Vanadium chloride cfalorination oat., 283 
Vanadium pentoxide oat., 260, 676, 603, 
702,828 

oxidation oat., 260, 260fi, 262n, 271 
Vanadium sulphate in sulphonation, 816 
Vanadoue oxide cat., 675 
Vanilline aoetylated, 240 

hydrogenated, 568 

by oxidation, 191, 249 
Vanilline triacetate, 240 
Various rings hydrogenated, 592, 603 
Velocity of oatalytic reactions, 23 
Vinyl bromide in F. and C. ^n., 889 
Vinylrtrimethylene hydrogenated, 577 
Volume of hydrogen req. by various oils, 
955 

Walls of yeasei as cat., 244fi 
Water as cat., 73, 249 

efifect on di^ydration, 710 

efifect on ethylene prep., 180% 

efifect on hydrogenation, 949 

neg. oat., 12 
Water gas, 398, 402 

for hydrogttiation, 953 

reducing agent, 511 
Wnbuschewitch's apparatus, 961 
Williamson's reaction, 159, 169 
Whale oU, 938 

efifect on oat., 947 
Woltman's apparatus, 964 
Wurts syn., 11 

Xylenes brominated, 292 
chlorinated, 278, 285 
add CO, 298 
from cracking, 908, 909 
from cymene, 930 
dec, by AlCla 887, 930 
by dehydrogenation, 641 



hydrogenated, 444, 447, 534, 560 

from pinene, 922 

isomer., 888 
Xylenols, ethen of, 786, 789 

hydrogenated, 458 
Xylonic add formed, 187 
Xylose, 188 

Zinc cat. cond. oat. 52, 795 

dec. alcohols, 670 

dehydrogenation cat., 670, 678 

in F. and C. syn., 899 

hydrogenation cat., 595 

oxidation cat., 269n 

polym. aids., 219 

toxic to cats., 115, 946 
Zinc bromide brominatioii cat. 293 

isom. cat., 200 
Zinc caibonate cat., 824 
Zinc chloride bromination cat., 293 

oat., 6, 89, 234, 240, 283, 633, 635, 687, 
689, 691, 695, 698 

cond. cat., 795, 796, 803 

eeterif. oat., 748, 761, 795 

in F. and C. syn., 899 

hydrol. cat., 330 

poljrm. cat., 211, 216, 222 
Zinc hydroxide isom. sugars, 186 
Zinc ongano-compounds, 304 
Zinc oxide cat., 75, 143, 539, 675, 676 

in cracking, 906, 934 

dec. formates, 809 

dehydration cat., 702 

dehydrogenation cat., 824 

hydration cat., 310 

ketone cat., 841, 849 
Ziroonia, amine cat., 732 

cat., 746, 791, 825, 840, 849 

esterification cat., 772n 

dec. formic ac, 624 

dehydration cat., 791 

dehydrogenation cat., 676, 693 

ketone cat, 840, 849 

mercaptan cat., 746 

mixed cat., 651, 675, 702 



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